JP4710192B2 - Control device for internal combustion engine with variable valve mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine including a variable valve mechanism that makes an operation state of an intake valve or an exhaust valve variable.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in the field of internal combustion engines, variable valve mechanisms that make the operating state (working angle and phase) of an intake valve or an exhaust valve variable are known. For example, Japanese Patent Laid-Open No. 4-187807 discloses a variable valve mechanism that makes the working angle and phase of the intake valve variable by moving the camshaft of the intake valve in the axial direction.
[0003]
The conventional variable valve mechanism includes a cam position sensor that detects the amount of movement of the camshaft. Based on the detection value of the cam position sensor, the movement amount of the camshaft is controlled so as to realize a desired operating angle and phase. According to such a mechanism, the intake valve can be opened and closed in an appropriate state according to the operating state of the internal combustion engine, and the output characteristics of the internal combustion engine can be improved.
[0004]
[Problems to be solved by the invention]
However, in the conventional variable valve mechanism described above, the camshaft position is affected by variations in the output characteristics of the cam position sensor, variations in its mounting position, and changes in sensor characteristics caused by temperature changes. May not be detected accurately. For this reason, depending on the conventional variable valve mechanism, it is difficult to always operate the intake valve (or the exhaust valve) in a desired state with high accuracy during operation of the internal combustion engine.
[0005]
The present invention has been made in order to solve the above-described problems. An internal combustion engine with a movable valve mechanism that can always operate an intake valve or an exhaust valve in a desired state with high accuracy during operation of the internal combustion engine. An object of the present invention is to provide an engine control device.
[0006]
[Means for Solving the Problems]
[0009]
Claim 1 The described invention is a control device for an internal combustion engine including a variable valve mechanism that makes an operation state of an intake valve or an exhaust valve variable,
A sensor that emits an output according to the operating state;
An actuator for changing the operating state, wherein each of the actuators realizes a known operating state at at least two reference positions;
Learning output detection means for detecting at least two learning outputs emitted from the sensor corresponding to the at least two reference positions;
Correction means for performing offset correction and gain correction of the sensor based on the at least two learning outputs;
Control means for controlling the actuator based on the output of the sensor after correction by the correction means and the operating state of the internal combustion engine,
The control means prohibits the control of the actuator based on the output of the sensor and the operating state of the internal combustion engine until two learning outputs are detected after the internal combustion engine is started, and two learning outputs are detected. After that,
The at least two reference positions include a minimum displacement end position that should be realized by the actuator when the internal combustion engine is idle, and a maximum displacement end position that is located opposite the minimum displacement end position.
Movable condition determining means for determining whether the movable condition of the actuator is satisfied after the internal combustion engine is started;
An actuator maintaining means for maintaining the actuator at the maximum displacement end position until the movable condition is satisfied after the internal combustion engine is started;
A minimum-side control means for controlling the actuator to a minimum-side displacement end position when idle operation is requested for the first time after the movable condition is established,
The learning output detection means includes a first detection means for detecting an output generated from the sensor corresponding to the maximum displacement end position immediately after the movable condition is satisfied, as a first learning output, and the actuator And second detection means for detecting an output generated from the sensor as a second learning output while being controlled to the minimum displacement end position.
[0010]
Claim 2 The described invention is claimed. 1 The control device for an internal combustion engine with a variable valve mechanism according to claim 1, wherein the learning output detection means updates the learning output every time a predetermined learning condition is satisfied during operation of the internal combustion engine. It is characterized by.
[0011]
Claim 3 The described invention is claimed. 2 The control apparatus for an internal combustion engine with a variable valve mechanism described in claim 1, further comprising forcible drive means for forcibly operating the actuator to a predetermined reference position when the predetermined learning condition is satisfied.
[0013]
Claim 4 The described invention is claimed. 3 A control device for an internal combustion engine with a variable valve mechanism described in
An output variable mechanism that varies the output of the internal combustion engine in a state in which the operation states of the intake valve and the exhaust valve are fixed;
When the actuator is forcibly driven by the forcible driving means, output control means for controlling the output variable mechanism so that an output change of the internal combustion engine accompanying the driving is canceled out;
It is characterized by providing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.
[0015]
Embodiment 1 FIG.
FIG. 1 is a conceptual diagram for explaining the configuration of the first embodiment of the present invention. The configuration shown in FIG. 1 includes an internal combustion engine 10. The internal combustion engine 10 includes an intake valve 12 and an exhaust valve 14. The intake valve 12 includes a variable valve mechanism 16 that varies the operation state of the intake valve 12 as a drive mechanism. Specifically, the variable valve mechanism 16 is a mechanism that varies the operating angle (valve opening period) of the intake valve 12 and the valve opening phase of the intake valve 12 with respect to the crank angle.
[0016]
A surge tank 20 communicates with the intake port 18 of the internal combustion engine 10. Further, an intake passage 22 is in communication with the surge tank 20. An electronic control throttle 24 is disposed inside the intake passage 22. An intake pipe internal pressure sensor 26 is inserted into the surge tank 20. Both the electronic control throttle 24 and the intake pipe internal pressure sensor 26 are connected to an ECU (Electronic Control Unit) 30.
[0017]
The ECU 30 is an electronic control unit that controls the operating state of the internal combustion engine 10. In addition to the electronic control throttle 24 and the intake pipe internal pressure sensor 26, an actuator 44 and a cam position sensor 32 (both described later) included in the variable valve mechanism 16 are connected to the ECU 30. Further, the ECU 30 includes a brake sensor 34 that is turned on when the brake pedal is depressed, an IG switch 36 that is turned on in conjunction with the operation of the ignition key, an NE sensor 38 that generates an output corresponding to the engine speed, and an accelerator pedal. An idle switch 40 that is turned on when is opened is connected.
[0018]
FIG. 2 is a conceptual diagram for explaining an example of the configuration of the variable valve mechanism 16. In the example shown in FIG. 2, the variable valve mechanism 16 includes an actuator 44 disposed at one end of the camshaft 42. The actuator 44 includes an oil control valve (OCV) 46 controlled by the ECU 30, and the oil is selectively supplied to one of the hydraulic chambers 48 and 50 by the OCV 46, thereby moving the cam shaft 42 in the axial direction thereof. Can be made.
[0019]
A plurality of three-dimensional cams 52 corresponding to individual cylinders of the internal combustion engine are fixed to the camshaft 42. The three-dimensional cam 52 is configured such that the height of the nose and the phase of the peak point of the nose change continuously according to the position of the camshaft 42 in the axial direction. More specifically, the three-dimensional cam 52 drives the intake valve 12 at the highest nose position when the camshaft 42 moves to the right displacement end position in FIG. 2, and the camshaft 42 is displaced to the left in FIG. The intake valve 12 is driven at the lowest nose position when moved to the end position, and the valve opening timing of the intake valve 12 is always constant regardless of the axial position of the camshaft 42. Yes.
[0020]
Therefore, according to the variable valve mechanism 16, by driving the actuator 44, the intake valve 12 can be changed without changing the valve opening timing of the intake valve 12 as indicated by the reference numeral (1) in FIG. 3. The valve opening period and the lift amount can be appropriately changed. Hereinafter, the position of the actuator 44 having the camshaft 42 as the right displacement end position described above (the position at which the maximum operating angle is achieved in the present embodiment) is referred to as “maximum side displacement end position”, and the camshaft 42 is described above. The position of the actuator 44 that is the left displacement end position (the position that achieves the minimum operating angle in this embodiment) is referred to as the “minimum side displacement end position”.
[0021]
In the present embodiment, the variable valve mechanism 16 further incorporates a rotation actuator (not shown) that rotates the camshaft 42 toward the advance side and the retard side with respect to the crank angle. Therefore, according to the variable valve mechanism 16, as indicated by the reference numeral (2) in FIG. 3, the relationship between the lift amount of the intake valve 12 and the crank angle is independent of the operating angle of the intake valve. It can be changed appropriately.
[0022]
In the configuration shown in FIG. 2, a cam position sensor 32 is disposed at the end of the camshaft 42. FIG. 4 shows an enlarged view of the cam position sensor 32. As shown in FIG. 4, the cam position sensor 32 includes a core 56 having a magnetic body 54 at the tip, and a coil 58 surrounding the core 56. The core 56 and the coil 58 constitute an operating transformer type non-contact stroke sensor. The core 56 is fixed to the end of the camshaft 42 (see FIG. 2). Therefore, the cam position sensor 32 generates an output corresponding to the position of the cam shaft 42 in the axial direction.
[0023]
FIG. 5 shows the relationship between the stroke of the cam position sensor 32 and the output. FIG. 6 shows the relationship between the stroke of the cam position sensor 32, that is, the stroke in the axial direction of the camshaft 42 and the operating angle of the three-dimensional cam 52. As shown in these drawings, the relationship between the cam position sensor 32 and the stroke and the relationship between the stroke and the operating angle are uniquely determined. Therefore, the ECU 30 can detect the operating angle of the three-dimensional cam 52 based on the output of the cam position sensor 32.
[0024]
FIG. 7 is a diagram for explaining the contents of intake valve control performed by the ECU 30 in the present embodiment. In FIG. 7, a line denoted by reference numerals (3) to (6) is an equiangular line of the operating angle that the intake valve 12 should realize. Here, these equiangular lines (3)-(6) represent larger working angles as the number increases.
[0025]
The ECU 30 stores in advance as a map the relationship shown in FIG. 7, that is, the relationship between the equiangular line of the operating angle to be given to the intake valve 12 and the operating state of the internal combustion engine (engine speed NE and required torque). Yes. Then, the ECU 30 determines a target value of the operating angle according to the engine speed and the required torque based on the map. As a result, in the system of this embodiment, the target value of the operating angle is set to a small value during low load operation where the engine speed is low and the required torque is small, while on the other hand, during high load operation where the engine speed is high and the required torque is large. The target value of the operating angle is set to a large value.
[0026]
After determining the target value of the operating angle as described above, the ECU 30 drives the actuator 44 so that the target value is realized. More specifically, the ECU 30 drives the actuator 44 so that the stroke detected by the cam position sensor 32 becomes a value corresponding to the target operating angle. Therefore, in the system of this embodiment, in order to control the operating angle of the intake valve 12 to the target value with high accuracy, the output of the cam position sensor 32 should correspond to the operating angle of the intake valve 12 with high accuracy. is necessary.
[0027]
By the way, the output of the cam position sensor 32 may shift to the high output side or the low output side with respect to the reference output to be originally output due to individual differences of the sensors or variations in the attachment position ( (See FIG. 8). Further, the output gain of the cam position sensor 32 may be larger or smaller than the reference gain that should be originally realized due to individual differences of sensors, temperature changes of the sensors, and the like (see FIG. 9). .
[0028]
For this reason, in order to always control the operating angle of the intake valve 12 to a desired angle with high accuracy during the operation of the internal combustion engine 10, it is possible to remove the influence of the shift and gain deviation described above from the output of the cam position sensor 32. is necessary. Hereinafter, with reference to FIG. 10, the contents of processing executed by the system of the present embodiment to realize the above-described function will be described.
[0029]
FIG. 10 is a flowchart of a learning routine that is executed by the ECU 30 in order to learn the output characteristics of the cam position sensor 32 in the present embodiment. The routine shown in FIG. 10 is a routine that is repeatedly activated every predetermined time (for example, 8 msec).
[0030]
In the routine shown in FIG. 10, first, it is determined whether or not the movable condition of the variable valve mechanism 16 is satisfied (step 100).
In the present embodiment, since the variable valve mechanism 16 is driven by hydraulic pressure, the movable condition is that the oil temperature exceeds 30 ° C. from the viewpoint of ensuring the driving stability. For this reason, in this step 100, when the condition of oil temperature> 30 ° C. is satisfied, it is determined that the movable condition is satisfied.
[0031]
If it is determined in step 100 that the movable condition of the variable valve mechanism 16 has not yet been established, the fixed working angle operation is performed thereafter (step 102).
The fixed working angle operation is an operation in a mode in which the internal combustion engine 10 is operated in a state where the working angle of the intake valve 12 is fixed to a predetermined value. In the present embodiment, the fixed working angle operation is specifically performed in a state where the actuator 44 shown in FIG. 2 is fixed at the maximum displacement end position. Therefore, the internal combustion engine 10 is operated in a state where the operating angle of the intake valve 12 is maximized until the movable condition of the variable valve mechanism 16 is satisfied.
[0032]
In the routine shown in FIG. 10, if it is determined in step 100 that the movable condition of the variable valve mechanism 16 is satisfied, it is then determined whether the establishment is determined for the first time after the IG switch is turned on. (Step 104).
[0033]
As a result, when it is determined that the movable condition is established for the first time after the IG switch is turned on, the actuator 44 is driven to the maximum displacement end position in order to maximize the operating angle of the intake valve 12. (Step 106).
As described above, in this embodiment, the actuator 44 is fixed at the maximum displacement end position until the movable condition is satisfied. Accordingly, the position of the actuator 44 does not substantially change even when the processing of step 106 is executed. For this reason, the output of the internal combustion engine 10 does not change at all before and after the execution of step 106. That is, according to the series of processes described above, it is possible to create a state in which the actuator 44 is controlled to the maximum displacement end position without changing the output of the internal combustion engine 10.
[0034]
After the actuator 44 is controlled to the maximum displacement end position, in the routine shown in FIG. 10, the sensor output corresponding to that position (the output of the cam position sensor 32) is learned (step 108).
[0035]
Next, it is determined whether a condition for switching the position of the actuator 44 from the maximum displacement end position to the minimum displacement end position is satisfied (step 110).
The minimum displacement end position is a position where the operating angle of the intake valve 12 is minimized. This minimum working angle is a working angle to be used when the load of the internal combustion engine 10 is sufficiently small as shown in FIG. For this reason, in step 110, when the idling operation is requested for the internal combustion engine 10, more specifically, the idling switch is turned off (the accelerator pedal is released) and the brake pedal is depressed. If it is determined that the above switching condition is satisfied, it is determined.
[0036]
In the routine shown in FIG. 10, the processing of step 110 is repeatedly executed until the above switching condition is satisfied. If it is determined in step 110 that the switching condition is satisfied, then the actuator 44 is driven to the minimum displacement end position in order to minimize the operating angle of the intake valve 12 (step 112).
[0037]
As described above, in the present embodiment, the process of step 112 is executed under a situation where idle operation is requested. That is, under the situation where the working angle of the intake valve 12 is inherently minimized, processing for minimizing the working angle is performed. For this reason, according to the series of processes described above, it is possible to create a state in which the actuator 44 is controlled to the minimum displacement end position without giving the driver an uncomfortable feeling with respect to the output of the internal combustion engine 10.
[0038]
After the actuator 44 is controlled to the minimum displacement end position, in the routine shown in FIG. 10, the sensor output corresponding to that position (the output of the cam position sensor 32) is learned (step 114).
[0039]
According to the series of processes described above, after the movable condition of the variable valve mechanism 16 is established, the cam position sensor 32 corresponding to the maximum displacement end position is not given to the driver with respect to the output of the internal combustion engine 10. And the output of the cam position sensor 32 corresponding to the minimum displacement end position can be learned. Hereinafter, the former is referred to as “maximum learning value” and the latter is referred to as “minimum learning value”.
[0040]
The maximum displacement end position is a position that creates a known state in which the operating angle of the intake valve 12 is maximized, that is, one of the reference positions in the actuator 44. The maximum learning value learned in step 108 is the output of the cam position sensor 32 corresponding to the reference position.
[0041]
Similarly, the minimum displacement end position is a position that creates a known state in which the operating angle of the intake valve 12 is minimized, that is, a second reference position in the actuator 44. The minimum learning value learned in step 114 is the output of the cam position sensor 32 corresponding to the second reference position.
[0042]
In the present embodiment, the ECU 30 stores characteristics as indicated by bold lines in FIG. 8 or FIG. 9, that is, characteristics of the reference output of the cam position sensor 32. According to this characteristic, when the actuator 44 is at the maximum displacement end position, the reference value of the output to be emitted from the cam position sensor 32 (hereinafter referred to as “maximum reference value”), and the actuator 44 is the minimum. A reference value (hereinafter referred to as “minimum side reference value”) of an output to be emitted from the cam position sensor 32 when the side displacement end position is set can be known.
[0043]
When the maximum reference value and the minimum reference value are known, the shift amount of the output of the cam position sensor 32 and the gain shift amount are detected by comparing them with the maximum learning value and the minimum learning value. Can do. Therefore, according to the system of the present embodiment, after the movable condition of the variable valve mechanism 16 is established, the shift amount and the gain shift amount superimposed on the output of the cam position sensor 32 at that time are accurately detected. be able to.
[0044]
In the routine shown in FIG. 10, when it is determined in step 104 that the movable condition is not established for the first time after the IG switch is turned on, the variable working angle operation is performed thereafter (step 116). .
The variable working angle operation is an operation in a mode in which the working angle of the intake valve 12 is appropriately changed according to the operating state of the internal combustion engine 10. In the present embodiment, the variable working angle operation is specifically performed so that the working angle of the intake valve 12 becomes a value adapted to the map shown in FIG. 7 based on the engine speed NE and the torque generated by the internal combustion engine 10. This is realized by controlling the actuator 44. A method for controlling the actuator 44 during execution of the variable working angle operation will be described in detail later with reference to FIG.
[0045]
In the routine shown in FIG. 10, it is determined whether or not the operation angle of the intake valve 12 is required to be minimized following the processing of step 116, more specifically, whether the internal combustion engine 10 is in an idle state. (Step 118).
[0046]
As a result, when it is determined that the internal combustion engine 10 is not in an idle state, the current routine is terminated without any further processing. On the other hand, when it is determined that the internal combustion engine 10 is in the idle state, it is determined whether or not a predetermined calibration condition is satisfied (step 120).
[0047]
The output characteristics (shift amount, gain deviation) of the cam position sensor 32 may change due to a temperature change or the like while the operation of the internal combustion engine 10 is continued. Therefore, in order to maintain high cam position detection accuracy by the cam position sensor 32, it is effective to update the maximum learning value and the minimum learning value at an appropriate timing during the operation of the internal combustion engine 10. .
[0048]
In the system of this embodiment, when the internal combustion engine 10 is in an idle state, those learning values are updated. The above-described calibration conditions are conditions determined so as to be satisfied particularly at the timing when the maximum learning value is to be updated. Therefore, when it is determined in step 120 that the calibration condition is not satisfied, the update process of the minimum learning value is performed thereafter, and on the other hand, it is determined that the calibration condition is satisfied. Then, the update process of the maximum learning value is performed.
[0049]
In this embodiment, for example, the elapsed time from the time when the maximum learning value was last updated has reached a predetermined time, the travel distance from that time has reached a predetermined distance, or from that time The fact that the integrated intake air amount has reached a predetermined amount can be used as a calibration condition. According to such a calibration condition, it is possible to appropriately update both the maximum learning value and the minimum learning value at appropriate intervals.
[0050]
If it is determined in step 120 that the calibration condition is not satisfied in the routine shown in FIG. 10, specifically, the actuator 44 is then controlled to the minimum displacement end position (step 122).
[0051]
Next, the minimum learning value is updated based on the output generated from the cam position sensor 32 in that state (step 124).
[0052]
The minimum displacement end position realized by the process of step 122 is a position that the actuator 44 should originally realize during the idling operation of the internal combustion engine 10. Therefore, according to the above-described series of processing, during operation of the internal combustion engine 10, the actuator 44 is controlled to the minimum displacement end position (reference position) without causing any unnatural fluctuations in the output, and the driver The minimum learning value can be updated without causing any sense of incongruity.
[0053]
If it is determined in step 120 that the calibration condition is satisfied in the routine shown in FIG. 10, then the actuator 44 is controlled to the maximum displacement end position (step 126) and the electronic control throttle 24 is set to a predetermined value. The valve is closed to the opening degree (step 128).
[0054]
Next, the maximum learning value is updated based on the output generated from the cam position sensor 32 in that state (step 130).
[0055]
In the system of the present embodiment, the intake pipe pressure PM is normally set to a pressure close to atmospheric pressure by opening the electronic control throttle 24 sufficiently large. In addition, the intake air amount is controlled by appropriately controlling the operating angle (valve opening period) of the intake valve 12. Such control is effective in suppressing the pumping loss of the internal combustion engine 10 and improving its fuel consumption characteristics.
[0056]
According to the process of step 126, the operating angle of the intake valve 12 is controlled to the maximum by controlling the actuator 44 to the maximum displacement end position. If this control is performed while the electronic control throttle 24 is largely opened, the intake air amount increases, and as a result, the output of the internal combustion engine 10 increases rapidly. In step 128, in order to suppress such an output change of the internal combustion engine 10, the electronic control throttle 24 is set to a predetermined opening degree so that the intake air amount does not increase with the increase of the operating angle of the intake valve 12. The valve is closed. For this reason, according to the processing of steps 126 to 130 described above, the maximum learning value can be updated without greatly changing the output during the idling operation of the internal combustion engine 10.
[0057]
As described above, according to the routine shown in FIG. 10, during operation of the internal combustion engine 10, both the maximum learning value and the minimum learning value are set at appropriate intervals without giving the driver a sense of incongruity with respect to the output. It can be updated at. For this reason, according to the system of the present embodiment, even if the characteristics of the cam position sensor 32 change due to a temperature change or the like, the maximum learning value and the minimum learning value can appropriately follow the change. it can.
[0058]
Next, with reference to FIG. 11, the actuator 44 is driven using the maximum learning value and the minimum learning value, more specifically, with respect to the main part of the processing executed by the ECU 30 to realize the variable working angle operation. A series of processes to be performed for this purpose will be described.
[0059]
In the course of the routine shown in FIG. 11, the ECU 30 detects the output of the cam position sensor 32 (step 200).
The output detected at this time is a result of superimposing a shift due to variations in sensor mounting position or the like, or a gain shift due to a temperature change or the like.
[0060]
Next, the maximum learning value and the minimum learning value learned by the routine shown in FIG. 10 are read (step 202).
[0061]
Next, the cam position is calculated based on the sensor output detected in step 200 and the maximum and minimum learning values read in step 202 (step 204).
[0062]
Specifically, in step 204, first, the output gain of the cam position sensor 32, that is, the slope of the output change with respect to the change in the stroke, is obtained based on the maximum learning value and the minimum learning value. Next, a correction coefficient for matching the inclination with the inclination of the reference output stored in the ECU 30 is obtained. Next, the shift amount superimposed on the output of the cam output sensor 32 is detected based on the difference between the maximum learning value and the maximum reference value or the difference between the minimum learning value and the minimum reference value. Once the correction coefficient and the shift amount are obtained, the output of the cam position sensor 32 is then corrected based on these values so that the effects of the output shift and gain deviation are offset. As a result, an output to be output when the cam position sensor 32 exhibits the reference output characteristic is obtained as a correction output. Then, the cam position (stroke) is calculated based on the correction output thus obtained and the reference output map stored in advance in the ECU 30 (see FIGS. 8 and 9).
[0063]
In the routine shown in FIG. 11, next, the actuator 44 is driven so that the cam position calculated in step 204 approaches the target cam position (step 206).
[0064]
While the variable working angle operation is being executed, the series of processes described above are repeatedly executed at predetermined time intervals. Further, the learning value read in step 202 is appropriately updated at an appropriate interval after the internal combustion engine 10 is started by the routine shown in FIG. For this reason, according to the system of the present embodiment, the intake valve is always accurately and accurately executed during the variable working angle operation regardless of the variation in the mounting position of the cam position sensor 32 or the occurrence of gain deviation due to temperature change. The 12 working angles can be continuously controlled to a desired angle.
[0065]
By the way, in Embodiment 1 mentioned above, although the cam position sensor 32 is limited to an operation | movement transformer type sensor, this invention is not limited to this. The cam position sensor 32 may be, for example, a contact type stroke sensor such as a potentiometer. When the actuator that drives the cam shaft 42 includes a rotating machine such as a motor or a speed reducer, the cam position sensor may be configured by an angle sensor that detects the rotation angle of the rotating machine.
[0066]
In the first embodiment described above, the operating angle of the intake valve 12 is maximized until the movable condition of the variable valve mechanism 16 is satisfied in step 102 in the routine shown in FIG. Is not limited to this. That is, the working angle given to the intake valve 12 before the movable condition of the variable valve mechanism 16 is satisfied is a general angle that is expected to be most commonly used under such operating conditions. Also good.
[0067]
When the above general angle is used, it is necessary to change the operating angle of the intake valve 12 from the general angle to the maximum operating angle immediately after the movable condition is established. In this case, in addition to the processing in step 106, processing similar to that in step 128, that is, processing for appropriately closing the electronic control throttle 24 may be executed to suppress changes in the output of the internal combustion engine 10.
[0068]
In the first embodiment described above, since the cam position sensor 32 shows a linear output change with respect to the stroke change, the learning value is acquired only at the two positions of the minimum displacement end position and the maximum displacement end position. However, the number of positions from which learning values are acquired is not limited to this. In other words, if the actuator that changes the operating angle has a reference position that can create a known operating state in addition to the maximum displacement end position and the minimum displacement end position, learning is performed at three or more reference positions. It is good also as acquiring a value.
[0069]
In Embodiment 1 described above, the variable valve mechanism 16 is used as a mechanism for changing the operating angle of the intake valve 12, but the present invention is not limited to this, and the variable valve mechanism 16 is not limited thereto. May be used as a mechanism for changing the operating angle of the exhaust valve 14.
[0070]
Further, in the first embodiment described above, the shift amount and gain deviation of the sensor that detects the operating angle (strictly, the cam position) of the intake valve 12 are targeted for correction, but the correction target is such a sensor. It is not limited to output. That is, according to the present invention, the shift amount and gain deviation of the sensor that detects the phase and lift amount of the intake valve 12 and the exhaust valve 14 may be corrected.
[0071]
Further, in the above-described first embodiment, after the movable condition of the variable valve mechanism 16 is established, first, the maximum learning value is learned (steps 106 and 108), and then the minimum is obtained when idle operation is requested. The side learning value is learned (steps 110 to 114). However, the method of acquiring the maximum learning value and the minimum learning value immediately after the above movable condition is satisfied is not limited to this. For example, if the internal combustion engine 10 is in idle operation when the movable condition of the variable valve mechanism 16 is established, the minimum learning value is first obtained at that time, and then the maximum is waited for the idle operation to exit. On the other hand, when the internal combustion engine 10 is not in idle operation at the time when the movable condition is satisfied, the maximum learning value is first acquired at that time, and then waiting for idle operation to be performed. The minimum learning value may be acquired. Even with such a method, both the maximum learning value and the minimum learning value can be acquired without causing a large change in the output of the internal combustion engine 10.
[0072]
Further, in the first embodiment described above, a technique for forcibly driving the actuator 44 to a desired reference position (maximum displacement end position) and controlling the electronic control throttle 24 (see steps 126 and 128), Although two or more learning values are used in combination with a learning technique, the present invention is not limited to this. That is, the former technique may be used in combination with a technique of learning only one learning value and correcting only the shift amount of the sensor output based on the learning value.
[0073]
In the first embodiment described above, when the actuator 44 is forcibly driven to a desired reference position (maximum displacement end position), the electronic control throttle 24 is closed to reduce the output fluctuation of the internal combustion engine 10. Although it is suppressed, the method of suppressing the output fluctuation is not limited to this. For example, it is possible to suppress an output change accompanying the forced drive of the actuator 44 by changing the ignition timing or by changing the fuel injection amount.
[0074]
In the first embodiment described above, the operating angle (ie, cam position) of the intake valve 12 is the above-mentioned claim. 1 In the “operating state” described above, the cam position sensor 32 is the claim. 1 It corresponds to each “sensor” described. Further, the ECU 30 executes the processing of steps 108, 114, 124, and 130, thereby making the claim. 1 The "learning output detection means" described above executes the processing of step 204, wherein 1 The "correction means" described above executes the process of step 206, and thereby 1 Each of the “control means” described is realized.
[0075]
Further, in the above-described first embodiment, the ECU 30 executes the processing of steps 100 to 116 described above, thereby making the claim. 1 The described “control means” is realized.
[0077]
Further, in the above-described first embodiment, the ECU 30 executes the process of step 100 described above, thereby making the above-mentioned claim. 1 The above-mentioned “movable condition determining means” executes the processing of steps 100 and 102 described above. 1 The above-mentioned “actuator maintaining means” executes the processing of steps 110 and 112 described above. 1 The "minimum side control means" described above executes the process of the step 108, so that the claim is made. 1 The "first detecting means" described above executes the process of step 114, wherein 1 The “second detection means” described is realized.
[0078]
In the first embodiment described above, the ECU 30 executes the processing of steps 118, 124, and 130 described above. 2 The described “learning output detection means” is realized.
[0079]
Further, in the first embodiment described above, the ECU 30 executes the process of step 126 described above, so that 3 The described “forced driving means” is realized.
[0081]
In the first embodiment described above, the electronic control throttle 24 corresponds to the “output variable mechanism” described in claim 5, and the ECU 30 executes the process of step 128 described above. 4 The described “output control means” is realized.
[0082]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
According to the first aspect of the present invention, sensor outputs corresponding to at least two reference positions that realize a known operation state can be detected as a learning output. According to these learning outputs, it is possible to detect the offset amount of the sensor output and the shift amount of the gain and correct them. According to the present invention, the operation state of the intake valve or the exhaust valve can be appropriately controlled based on the sensor output corrected in this way.
[0083]
Also, Claim 1 According to the described invention, after the internal combustion engine is started, control of the operation state of the intake valve or the exhaust valve based on the operation state of the internal combustion engine is prohibited until learning about the sensor output is completed. Therefore, according to the present invention, it is possible to prevent the intake valve or the exhaust valve from being controlled to an inappropriate state due to variations in sensor output or the like.
[0085]
Also, Claim 1 According to the described invention, the actuator is fixed at the maximum displacement end position before the movable condition is satisfied, and learning corresponding to the maximum displacement end position is performed immediately after the movable condition is satisfied. For this reason, according to the present invention, learning corresponding to the maximum displacement end position can be executed without causing output fluctuation of the internal combustion engine before and after the movable condition is established.
[0086]
Claim 2 According to the described invention, the learning output can be repeatedly updated during the operation of the internal combustion engine. For this reason, according to the present invention, the sensor output after correction can always be maintained at an appropriate value following the variation in the sensor output caused by a temperature change or the like.
[0087]
Claim 3 According to the described invention, the learning output can be forcibly obtained by forcibly driving the actuator.
[0088]
Claim 4 According to the described invention, while the actuator is forcibly driven, the variable output mechanism can be controlled so that the change in the output of the internal combustion engine accompanying the drive is canceled out. For this reason, according to the present invention, it is possible to forcibly obtain a learning output without accompanying an output change of the internal combustion engine.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining an overview of a system according to a first embodiment of the present invention;
2 is a diagram for explaining a configuration of a variable valve mechanism provided in the internal combustion engine shown in FIG. 1; FIG.
FIG. 3 is a view for explaining the function of the variable valve mechanism shown in FIG. 2;
4 is an enlarged view of a configuration of a cam position sensor provided in the variable valve mechanism shown in FIG. 2. FIG.
FIG. 5 is a diagram showing output characteristics of the cam position sensor shown in FIG.
6 is a diagram showing a relationship between a stroke realized by the variable valve mechanism shown in FIG. 2 and an intake valve operating angle. FIG.
FIG. 7 is a diagram showing the working angle of the intake valve to be realized in the system of Embodiment 1 in relation to the engine speed and the engine torque.
FIG. 8 is a diagram for explaining an influence of a shift superimposed on an output of a cam position sensor.
FIG. 9 is a diagram for explaining an influence of a gain shift superimposed on an output of a cam position sensor.
FIG. 10 is a flowchart of a routine that is executed in order to learn the output characteristics of the cam position sensor in the system according to the first embodiment.
FIG. 11 is a flowchart showing the contents of a series of processing executed to control the operating angle of the intake valve in the system of the first embodiment.
[Explanation of symbols]
10 Internal combustion engine
12 Intake valve
14 Exhaust valve
16 Variable valve mechanism
24 Electronically controlled throttle
30 ECU (Electronic Control Unit)
32 Cam position sensor
42 Camshaft
44 Actuator
52 3D cam

Claims (4)

A control device for an internal combustion engine comprising a variable valve mechanism that varies an operating state of an intake valve or an exhaust valve,
A sensor that emits an output according to the operating state;
An actuator for changing the operating state, wherein each of the actuators realizes a known operating state at at least two reference positions;
Learning output detection means for detecting at least two learning outputs emitted from the sensor corresponding to the at least two reference positions;
Correction means for performing offset correction and gain correction of the sensor based on the at least two learning outputs;
Control means for controlling the actuator based on the output of the sensor after correction by the correction means and the operating state of the internal combustion engine,
The control means prohibits the control of the actuator based on the output of the sensor and the operating state of the internal combustion engine until two learning outputs are detected after the internal combustion engine is started, and two learning outputs are detected. After that,
The at least two reference positions include a minimum displacement end position that should be realized by the actuator when the internal combustion engine is idle, and a maximum displacement end position that is located opposite the minimum displacement end position.
Movable condition determining means for determining whether the movable condition of the actuator is satisfied after the internal combustion engine is started;
An actuator maintaining means for maintaining the actuator at the maximum displacement end position until the movable condition is satisfied after the internal combustion engine is started;
A minimum-side control means for controlling the actuator to a minimum-side displacement end position when idle operation is requested for the first time after the movable condition is established,
The learning output detection means includes a first detection means for detecting an output generated from the sensor corresponding to the maximum displacement end position immediately after the movable condition is satisfied, as a first learning output, and the actuator Control of an internal combustion engine with a variable valve mechanism, comprising: second detection means for detecting an output generated from the sensor as a second learning output while being controlled to the minimum displacement end position. apparatus. The learning output detecting means, during the operation of the internal combustion engine, each time the predetermined learning condition is satisfied, a variable valve mechanism with an internal combustion engine according to claim 1, wherein the updating of the output the learning Control device. 3. The control apparatus for an internal combustion engine with a variable valve mechanism according to claim 2 , further comprising forcible drive means for forcibly operating the actuator to a predetermined reference position when the predetermined learning condition is satisfied. An output variable mechanism that varies the output of the internal combustion engine in a state in which the operation states of the intake valve and the exhaust valve are fixed;
When the actuator is forcibly driven by the forcible driving means, output control means for controlling the output variable mechanism so that an output change of the internal combustion engine accompanying the driving is canceled out;
The control apparatus for an internal combustion engine with a variable valve mechanism according to claim 3 .

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