Controls

Abstract

The present invention provides a control device that can calculate a cam phase equal to the actual cam angle even when the change in cam phase caused by a variable valve mechanism exceeds the corresponding cam angle signal detection range. In addition to the existing cam angle measurement function, it also includes a cam angle measurement unit for when the cam angle exceeds the cam angle measurement reference position and is advanced or delayed, and a unit for judging whether the cam angle signal exceeds the cam angle measurement reference position and is advanced or delayed. By switching the cam angle measurement function according to the judgment result of whether the cam angle signal exceeds the cam angle measurement reference position, the cam phase change amount can maintain the same wide angle as the existing one, while improving the time resolution of the angle measurement.

Description

Technical Field

[0001] The invention relates to a control device. Background Art

[0002] In order to improve fuel efficiency, an increasing number of engines are equipped with variable valve mechanisms that allow the opening and closing timing of intake and exhaust valves to be variable according to the engine state. Under the control of the variable valve, the phase change of the detected cam angle signal is fed back to the controller of the variable valve device, and the cam phase is controlled to a target phase. Patent document 1 shows a basic concept related to a method for measuring a cam phase angle.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-20707 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In order to suppress the fluctuation of EGR gas during transient operation or to cope with a high-precision torque control request, a high response of the variable valve mechanism is required. Therefore, in order to improve the measurement time resolution, a cam signal plate with a larger number of teeth than conventional ones is sometimes used.

[0008] In the technology of the above-mentioned patent document 1, the change angle of the cam phase is calculated within the range of the cylinder phase angle (the compression TDC interval of each cylinder). However, for this technology, if a cam signal plate with a larger number of teeth than the existing one is used, multiple cam angle signals are detected within the range of the cylinder phase angle, and the change angle of the cam phase cannot be correctly calculated.

[0009] In this case, the cam angle signal detection range is set to an angle narrower than the cylinder phase angle (for example, the angle obtained by dividing one cycle angle by the number of cam teeth), so that the detection teeth of the cam signal plate and the cam angle signal detection range correspond one-to-one, and each cam angle signal is detected independently. This can avoid detecting multiple cam angle signals within one cam angle signal detection range.

[0010] However, the variable range of the cam phase of the variable valve mechanism is determined by various performance requirements of the internal combustion engine that are different from the above conditions. Therefore, when the cam phase angle is advanced or delayed due to the variable valve mechanism, and the corresponding detection tooth exceeds the corresponding cam angle signal detection range and moves to the adjacent cam angle signal detection range, an incorrect cam phase may be calculated.

[0011] An object of the present invention is to provide a control device capable of calculating a cam phase equal to an actual cam angle even when a change in cam phase due to a variable valve mechanism exceeds a corresponding cam angle signal detection range.

[0012] Methods for solving problems

[0013] In order to solve the above-mentioned problems, the present invention includes a control device, which is characterized in that: it is determined whether there are signs of exceeding the action in which the cam phase changes beyond the cam angle signal detection range, and when it is determined that there are signs of exceeding the action, when the cam angle signal is detected outside the cam angle signal detection range, the cam phase angle calculation formula is changed.

[0014] Effects of the Invention

[0015] According to the present invention, even if a cam signal plate having a number of teeth corresponding to the high speed of the variable valve mechanism is used, the amount of change of the cam phase consistent with the actual situation can be calculated. Therefore, the fuel efficiency improvement and torque control effect achieved by the high-precision intake and exhaust valve opening and closing timing control can be obtained without reducing the action range of the phase angle.

[0016] Further features related to the present invention are apparent from the description of this specification and the accompanying drawings. In addition, other problems, structures and effects than those described above will become clear from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram for explaining the structure of a variable valve mechanism of an internal combustion engine.

[0018] Figure 2 This is a block diagram for explaining the functional structure of a conventional control device.

[0019] Figure 3 This is a diagram for explaining a conventional working angle measurement method.

[0020] Figure 4 This is a diagram for explaining the effect of improving measurement resolution.

[0021] Figure 5 This is a diagram for explaining the problems of the conventional method.

[0022] Figure 6 This is a diagram for explaining a solution to a conventional problem.

[0023] Figure 7 This is a diagram for explaining the features of a measuring method according to one embodiment of the control device of the present invention.

[0024] Figure 8 This is a diagram for explaining a method of setting the width of the cam angle signal determination range.

[0025] Fig. 9 This is a block diagram for explaining the internal functional configuration of the control device according to the first embodiment.

[0026] Fig.10 This is a block diagram for explaining the internal functional structure of the cam angle excess determination unit.

[0027] Fig.11 This is a graph showing changes in the output of the cam angle excess determination unit corresponding to the operating angle.

[0028] Fig.12 This is a flowchart showing the processing contents of the cam angle signal excess sign determination unit.

[0029] Fig.13 This is a block diagram for explaining the internal functional configuration of the working angle calculation unit according to the second embodiment.

[0030] Fig.14 This is a flowchart showing the processing contents of the working angle calculation unit.

[0031] Fig.15 This is a diagram for explaining a conventional working angle measurement method.

[0032] Fig.16 This is a diagram for explaining the problems of the conventional method.

[0033] Fig.17 This is a diagram for explaining the features of a measuring method according to one embodiment of the control device of the present invention.

[0034] Fig.18 This is a diagram for explaining a solution to a conventional problem.

[0035] Fig.19 This is a graph showing changes in the output of the cam angle excess determination unit corresponding to the operating angle. DETAILED DESCRIPTION

[0036] <Example 1>

[0037] Embodiments of the cam angle measuring method of the present invention will be described with reference to the drawings.

[0038] use Figure 1 The structure of an internal combustion engine including a variable valve mechanism will be described.

[0039] The internal combustion engine burns a mixture of fuel and air in a space (cylinder) enclosed by a piston 101, an intake valve 102, and an exhaust valve 103, and converts the volume expansion of the combustion gas into the rotational motion of a crankshaft 100 connected to the piston 101. The rotation of the crankshaft 100 is transmitted to an intake camshaft 104 and an exhaust camshaft 106 via a timing belt 108 (which may also be a timing chain). The intake camshaft 104 and the exhaust camshaft 106 include an intake cam 105 and an exhaust cam 107. When the intake cam 105 pushes down the intake valve 102, the intake passage is opened, and air or a mixture of fuel and air flows into the cylinder. In addition, when the exhaust cam 107 pushes down the exhaust valve 103, the exhaust passage is opened, and the combustion gas is discharged from the cylinder.

[0040] The crank angle plate 109 fixed to the crankshaft 100 includes detection teeth provided at predetermined intervals. The crank angle sensor 110 reads the positions of the detection teeth as crank angle signals, thereby enabling the rotation angle or rotation speed of the crankshaft to be recognized.

[0041] The cam angle plate 111 fixed to the intake camshaft 104 includes detection teeth provided at predetermined intervals. The cam angle sensor 112 reads the positions of the detection teeth as cam angle signals, thereby enabling the rotation angle or rotation speed of the camshaft to be identified.

[0042] In a so-called multi-cylinder internal combustion engine including a plurality of pistons, the cylinder that will ignite the mixture next is identified (cylinder identification) by combining angle information based on the crank angle signal and the number of detections or signal status (voltage level, etc.) of the cam angle signal.

[0043] Since the inertial force acts on the inhaled air, the amount of gas inhaled changes according to the engine speed when the opening and closing timing of the intake valve is fixed. Therefore, it is known that a technology for actively controlling the intake amount by making the opening and closing timing of the intake valve variable using a variable valve mechanism 113 is used. The variable valve mechanism 113 has a cam housing 115 whose phase is constant and a vane 116 fixed to the camshaft and changes the phase of the camshaft as main components. The variable valve mechanism 113 has an electrically controlled mechanism or a mechanism controlled by injecting hydraulic pressure into the gap 117 or 118. Taking hydraulic control as an example, it is possible to supply hydraulic pressure to the gap 117, change the phase of the camshaft in the camshaft rotation direction 114 by the rotation of the vane 116 (advance angle operation), or supply hydraulic pressure to the gap 118, change the phase of the camshaft in the direction opposite to the camshaft rotation direction 114 by the rotation of the vane 116 (retard angle operation).

[0044] In addition, the vane 116 determines the initial position by a key or spring force, and there is a structure in which the initial position is set at the most retarded angle position and the vane is controlled from the most retarded angle position to the advanced angle direction, or a structure in which the initial position is set between the most retarded angle position and the most advanced angle position and the vane is controlled in both the advanced angle direction and the retarded angle direction. In this embodiment, the structure in which the initial position is set at the most retarded angle position and the vane is controlled from the most retarded angle position to the advanced angle direction is described as an example, but the present invention is not limited to this structure.

[0045] The method of controlling the camshaft to a target angle by a variable valve mechanism is generally feedback control that calculates the current cam angle working amount (working angle) relative to the initial position and adjusts the control amount based on the difference between the cam angle and the target angle.

[0046] The control device of the present embodiment relates to a technology for calculating the operating angle of a cam shaft of a variable valve mechanism and measuring the cam phase.

[0047] Next, use Figure 2 The structure of a conventional control function related to operation angle calculation will be described. Figure 2 This is a block diagram for explaining the functional structure of a conventional control device. This function is included in the ECU 200 of the internal combustion engine.

[0048] In conventional control, the output of the crank angle sensor 213 is detected by the signal detection unit 203, and the crank angle information 210 for cam angle calculation is calculated by the angle generation unit 211 based on the detected crank angle signal 212. In addition, the output of the cam angle sensor 202 is detected by the signal detection unit 203, and the cam angle signal 204 is output.

[0049] The cam angle calculation unit 205 calculates the cam angle 209 based on the crank angle information 210 when the cam angle signal 204 with respect to the measurement reference position angle is input, including the measurement reference position angle of the cam angle in the crank angle information 210 .

[0050] The working angle calculation unit 206 includes the information of the cam angle at the initial position, compares the cam angle 209 calculated by the cam angle calculation unit 205 with the cam angle at the initial position, and calculates the working angle 208 of the camshaft. The working angle 208 is used for calculating the control parameter of the variable valve mechanism by the variable valve mechanism control parameter calculation unit 207. In addition, the control parameter calculated by the variable valve mechanism control parameter calculation unit 207 is used for the control of the variable valve mechanism, that is, the feedback control to the target angle.

[0051] use Figure 3 right Figure 2 The calculation contents of the cam angle calculation unit 205 and the working angle calculation unit 206 are described in detail. Figure 3 This is a diagram for explaining a conventional working angle measurement method.

[0052] Figure 3 This is a diagram for explaining a conventional working angle measurement method, with the horizontal axis being time and the vertical axis being the cam angle signal. Figure 3 The upper part of the figure shows a detection example 301 of the cam angle signal at the most retarded angle position. Figure 3 The lower section shows a detection example 302 of the cam angle signal at the position moved to the advance angle side.

[0053] Although the cam angle signal also depends on the specifications of the sensor, it is recorded as a specification that the signal level drops when the detection teeth of the cam angle plate 111 are detected. The time when the ECM detects the cam angle signal is T321~T323 and T321'~T323'. The time with a dash in the symbol means that the time without a dash in the symbol is the initial position. That is, the time indicated by the symbol without a dash is the detection time of the cam angle signal at the most retarded angle position, and the time indicated by the symbol with a dash is the detection time of the cam angle signal at the advanced angle moving position moving from the most retarded angle position to the advanced angle direction.

[0054] The cam angle signal is also used for cylinder discrimination, but the detection timing changes due to the variable valve mechanism, so the cam angle needs to be detected within a range where the cam angle signal input information (frequency or signal level) does not change. Therefore, the cam angle measurement range T311 to T313 (actually also continues to the right direction) is set as the cylinder phase difference interval (compression TDC interval). For example, in the case of a 3-cylinder internal combustion engine, it becomes a 240degCA interval, and in the case of a 4-cylinder internal combustion engine, it becomes a 180degCA interval.

[0055] As for the cam angle, the advance angle end T301 to T303 (actually, it also continues to the right direction) of the cam angle measurement range T311 to T313 is used as the cam angle measurement reference position, and the angle from the advance angle end T301 to T303 to the cam angle signal detection time T321 to T323, T321' to T323' is detected as the cam angle. For example, within the cam angle measurement range T312, the angle from the cam angle measurement reference position T302 to the detection time T322 when the cam angle signal is detected is the cam angle (initial position) 303 at the most retarded angle position. Moreover, within the same cam angle measurement range T312, the angle from the cam angle measurement reference position T302 to the detection time T322' when the cam angle signal is detected is the cam angle (operating position) 304 at the most advanced angle movement position. Furthermore, the difference between the cam angle (initial position) 303 and the cam angle (operating position) 304 is calculated as the operating angle (first operating angle) 305. This conventional calculation formula is the following formula (1).

[0056] Working angle = cam angle (initial position) - cam angle (working position)... (1)

[0057] In order to appropriately follow the changes in engine speed and control the variable valve mechanism, it is desirable that the cam angle detection frequency be high. Figure 4 , the following description will be given by taking the case where the camshaft angle is controlled from an initial angle to a target angle in the direction of an advance angle by a variable valve mechanism.

[0058] Figure 4 This is a diagram for explaining the effect of improving measurement resolution.

[0059] exist Figure 4 In FIG. 4 , the dotted line 402 indicates the action when the camshaft angle is controlled based on the detection value of the cam angle detected at a low detection frequency, and the solid line 401 indicates the action when the camshaft angle is controlled based on the detection value of the cam angle detected at a high detection frequency.

[0060] In the low detection frequency control for controlling the variable valve mechanism by calculating the cam operating angle at the time of T421 to T427, it is predicted at the detection time T422 that the target angle (413) will be exceeded at the next detection time T423 based on the results of the operating angles 411 and 412. Therefore, the angle control amount is reduced to control, and as a result, the time from the start of control to the target angle is T403, and the time between T401 and T403 is spent at T411.

[0061] On the other hand, if the detection time of T431 to T437 is added to the time of T421 to T427 to improve the time resolution of the working angle measurement, the working angle (414) of T432 predicted at T422 does not exceed the target angle. Therefore, the control can be performed without reducing the angle control amount, and the arrival time from the start of control to the target angle becomes T402, and the time from T401 to T402 can be set to T412, which is shorter than T411, so that high-speed target angle control can be performed.

[0062] In order to improve the time resolution of the working angle measurement, the cam angle signal detection frequency can be increased, and the detection teeth set on the cam angle plate can be increased and arranged at short intervals.

[0063] Next, use Figure 5 The following describes the problems of conventional control when a cam angle plate having a high time resolution and increased detection teeth is applied. Figure 5 This is a diagram for explaining the problems of conventional control.

[0064] For example, the cam angle sensor 202 sets a cam angle measurement range T511 to T515 corresponding to the number of teeth in order to detect the cam angle signal for each tooth of the cam angle plate independently. When a cam angle plate with high time resolution is used, the cam angle measurement range is narrower than when a conventional cam angle plate with a small number of teeth is used.

[0065] However, since the operating range of the variable valve mechanism is determined based on the performance requirements of the internal combustion engine, the same operating range as the existing one is considered. Figure 5 As in the example shown in the upper part of FIG. 1 , in which the cam angle signal T524 is advanced to the position T524 ′, consider a case where the cam angle is detected in the cam angle measurement range T512 that is adjacent to the cam angle measurement range T513 .

[0066] In this case, the camshaft actually works in the advance angle direction by an operating angle of 503, but within the cam angle measurement range T513, which sets T503 as the cam angle measurement reference position, the cam angles of T524 and T525' are compared and the operating angle 504 (lag value) is calculated (incorrect calculation). Figure 5 As shown in the lower part of , although the actual cam angle changes in a manner gradually increasing in the advance angle direction as shown by the dotted line 533, in the existing calculation method, the working angle 534 after exceeding the cam angle measurement reference position angle 532 (after T534) is calculated as the lag angle value.

[0067] When this value is fed back, the advance angle control is excessively performed toward the target angle 531 , so that the operating range of the variable valve mechanism is limited to the cam angle measurement range and narrowed so as not to exceed the measurement reference position 532 .

[0068] Next, based on Figure 6 A method for achieving high time resolution measurement without narrowing the operating range of the variable valve mechanism is described. Figure 6 This is a diagram for explaining a solution to a conventional problem.

[0069] For example, when the camshaft is advanced from the most retarded angle position due to the operation of the variable valve mechanism, such as Figure 6 As shown in the upper upper section to the upper lower section, when moving from cam angle signal T624 to cam angle signal T624', the working angle 603 of the cam angle signal detected at a position exceeding the cam angle measurement range T613 is composed of the cam angle (initial position) 601 and the conversion cam angle 604 from the cam angle measurement reference position T603 to T624'.

[0070] The conversion cam angle 604 is obtained from the cam angle 602 of the cam angle signal T624' and the angle of the cam angle measurement range T612 within the cam angle measurement range T612, and the above-mentioned cam angle measurement range T612 becomes another cam angle measurement range adjacent to the advance angle side with respect to the cam angle measurement range T613. That is, the angle obtained by subtracting the cam angle 602 from the angle of the cam angle measurement range T612 becomes the conversion angle of the cam angle 602, the conversion cam angle 604. The conversion cam angle 604 is an angle obtained by converting the operating cam angle of the other cam angle measurement range at the operating position of the variable valve into an advance angle direction value.

[0071] Therefore, the accurate operation angle (second operation angle) 603 in the advance angle direction is obtained by adding the cam angle (initial position) 601 and the conversion cam angle 604. The conversion cam angle calculation formula is the following calculation formula (2).

[0072] Working angle (when exceeded) = cam angle (initial position) + conversion cam angle (working position) ... (2)

[0073] exist Figure 6 In the lower part of the figure, the target angle 631 is set in the area exceeding the cam angle measurement reference position angle 632, and the calculation result of the measurement angle at the start of control is shown. In order to convert the cam angle detected before exceeding the cam angle measurement reference position angle 632 to the working angle, the existing calculation formula (1) is used. In addition, when converting the cam angle detected after exceeding the cam angle measurement reference position angle 632 to the working angle, the calculation formula for the working angle after T634 is changed from Figure 3 The existing calculation formula (1) described in Figure 6 The conversion cam angle described above is switched using the calculation formula (2), and the working angle 634 along the cam shaft motion 633 can be calculated without lag angle value and erroneous calculation. Therefore, even in the area where the cam angle exceeds the cam angle measurement reference position angle, high time resolution angle measurement can be achieved.

[0074] By appropriately changing the formula for calculating the operating angle in this manner, the operating angle of the cam can be accurately calculated even in a region where the cam angle exceeds the cam angle measurement reference position.

[0075] Next, a method for determining the switching of the operating angle calculation formula will be described.

[0076] The switching of the working angle calculation formula only requires the recognition of the situation where the cam angle signal exceeds the cam angle measurement reference position. However, it is necessary to distinguish whether the cam angle signal detected in the area exceeding the cam angle measurement reference position is based on the detection signal of the advance angle or the detection signal based on the lag angle. For example, it is necessary to distinguish Figure 7The cam angle signal T725" shown is an advance angle signal of T725 or a retard angle signal of T724. Therefore, a prescribed range in the retard angle direction from the cam angle measurement reference position is defined as a cam angle signal judgment range (701 to 706) as in the interval 704 from T704 to T714. When the cam angle changes in the advance angle direction and exceeds the cam angle measurement reference position and moves to other adjacent cam angle measurement ranges, it is determined whether the cam angle measurement reference position is exceeded by using a certain condition of passing through the cam angle signal judgment range.

[0077] That is, after detection within the cam angle signal determination range, the signal detected in the area exceeding the cam angle measurement reference position is determined to be based on the advance angle, and the cam angle is used. Figure 6 The conversion cam angle described in the above is applied to the working angle using the calculation formula (2).

[0078] The cam angle signal determination range is set in terms of either angle or time. In this embodiment, the description is given assuming that the range is set in terms of angle. Next, a method for determining the width of the cam angle signal determination range will be described.

[0079] The cam angle signal determination range must be a range that can reliably detect the advanced cam angle signal at least once. That is, if the width of the cam angle signal determination range is a width that is synchronized with the input speed of the cam angle signal, the cam angle signal can be reliably detected once. Figure 8 , since the input speed of the cam angle signal changes according to the operating speed of the variable valve mechanism or the engine speed, the case where it is set to a width corresponding to each parameter is described.

[0080] Figure 8 This is a diagram for explaining a method of setting the width of the cam angle signal determination range.

[0081] exist Figure 8 The upper part of the diagram shows an example of the operation of the variable valve mechanism at a high operating speed 801 and at a low operating speed 802 when the engine speed is high. The input cycle of the cam angle signal is represented by the interval T811 to T815. The input cycle is roughly determined by the engine speed, and the angle change is determined by the operating speed of the variable valve mechanism. If the angle change is large, the measurement reference position 805 is passed at a high speed, so in order to reliably capture the cam angle signal more than once, the width of the cam angle signal judgment range must be wide.

[0082] In case 802 where the variable valve mechanism operates at a relatively low operating speed, if the width of the cam angle signal determination range is set to 808, cam angle detection 811 within the cam angle signal determination range 808 can be performed at T804.

[0083] On the other hand, even if the same width 808 is applied to the case 801 where the variable valve mechanism operates at a higher operating speed, the cam angle cannot be detected at the time T801. Therefore, by expanding the width of the cam angle signal determination range from 808 to 809, the cam angle detection 810 can be performed at T801.

[0084] Next, in Figure 8 The lower part of 800 shows operation examples of a case 801 in which the variable valve mechanism operates at a relatively high operating speed and a case 802 in which the variable valve mechanism operates at a relatively low operating speed when the engine speed is low. The input cycle of the cam angle signal is represented by intervals T821 to T824.

[0085] Even if the cam angle signal determination range width 808 is applied when the engine speed is high when the variable valve mechanism is operated at a relatively low working speed 802, the cam angle 813 is out of the cam angle signal determination range width 808 at the time T822 and cannot be detected. Therefore, by expanding the cam angle signal determination range width from 808 to 808', the cam angle can be detected at T822. In the present embodiment, the cam angle signal determination range width 808 is expanded toward the side where the working angle degCA becomes smaller, and is set to width 809.

[0086] The same is true in the case 801 where the variable valve mechanism operates at a relatively high operating speed, for example Figure 8 As shown in the lower part of , by expanding the width from 809 to 809', the cam angle 812 can be detected at T821.

[0087] According to the above relationship between the operating speed of the variable valve mechanism and the cam angle signal input cycle, the width of the cam angle signal judgment range can be calculated by the product of the operating speed of the variable valve mechanism and the cam angle signal input cycle. The cam angle signal input cycle is synchronized with the engine speed, and the width of the cam angle signal judgment range can also be calculated by using the engine speed as a calculation parameter instead of the cam angle signal input cycle.

[0088] Compared with the existing functional structure, using Fig. 9 The functional structure of the present invention will be described.

[0089] Fig. 9 This is a block diagram for explaining the structure of the internal functions of the control device of the first embodiment. In the control device of this embodiment, a cam angle exceeding judgment unit 903 is newly added, and the cam angle exceeding judgment unit 903 is detected when the cam angle signal moves from the most retarded angle position to the advanced angle direction and exceeds the cam angle measurement reference position.

[0090] The operating angle calculation unit 905 is modified to change the calculation formula by referring to the determination result 904 of the cam angle excess determination unit 903. The calculation result 906 of the operating angle calculation unit 905 is output to the variable valve mechanism control parameter calculation unit 207 in the same manner as in the related art.

[0091] In addition, the cam angle input period calculation unit 901 is not included in Figure 2 In the structure shown, the input period calculation function is used for cylinder discrimination, etc., and is a known technology, so the function used in a function different from the cam angle measurement can be utilized or added for the present structure.

[0092] Next, use Fig.10 The functional structure of the cam angle excess determination unit 903 will be described.

[0093] The cam angle excess judgment unit 903 includes a cam angle signal excess sign judgment unit 1001 for judging whether the cam angle signal is detected within the cam angle signal judgment range through the advance angle of the cam angle, a cam angle signal lag angle judgment unit 1002 for judging whether the cam angle signal is detected at the lag angle side relative to the initial position within the cam angle measurement range, and a switching judgment unit 1003 for indicating the switching of the calculation formula used by the working angle calculation unit 905.

[0094] Next, use Fig.11 The timing diagram of the cam angle excess judgment unit is used to illustrate the functions of the cam angle excess judgment unit.

[0095] As an example, the camshaft is assumed to be advanced to a target operating angle 1104 exceeding a measurement reference position angle 1105 and then returned to an initial position angle 0degCA. The camshaft movement is shown as 1101 in the case where the camshaft temporarily moves in the retardation direction due to the design margin of the camshaft operating range or the relationship between the camshaft rotational force. The operation of the variable valve mechanism starts at T1100, and the cam angle signal is detected at the time of T1101 to T1121. The operating angle calculation result is shown as 1102.

[0096] In the cam angle signal exceeding sign judgment unit 1001, at T1103 when the cam angle signal is detected within the cam angle signal judgment range 1103, the cam angle signal exceeding sign judgment value is set to 1. The previous value is maintained while the cam angle exceeds the measurement reference position angle 1105 and advances. Furthermore, when the target working angle 1104 is shifted to the initial position, at T1113 when the cam angle is detected within the cam angle signal judgment range 1103, the cam angle signal exceeding sign judgment value is set to 1. Since the cam angle signal is detected at the lag angle side than the cam angle signal judgment range 1103 at T1114, the cam angle signal exceeding sign judgment value is set to 0.

[0097] In the cam angle signal retardation angle determination unit 1002, regardless of the operating direction of the cam shaft, when the cam angle calculation unit 205 calculates a value closer to the retardation angle side than the initial position, the cam angle signal retardation angle determination value is set to 1. Therefore, T1104 to T1113, T1120, and T1121 become 1. When the cam angle calculation unit 205 calculates a value closer to the advance angle side than the initial position, the cam angle signal retardation angle determination value is set to 0.

[0098] In the switching judgment unit 1003, when the cam angle signal exceeding sign judgment value 1121 is 1 and the cam angle signal lag angle judgment value 1122 is 1, it is judged that the cam angle is a value exceeding the measurement reference position angle 1105, and in order to switch the working angle calculation formula, the switching judgment value is set to 1. Therefore, in the interval T1132 from T1104 to T1113, the switching judgment value is set to 1. Since the conditions are not met in the other intervals T1131 or T1133, the switching judgment value is set to 0.

[0099] Next, use Fig.12 A control flow chart of the cam angle signal excess sign determination unit 1101 will be described. Fig.12 This is a flowchart showing the processing contents of the cam angle signal excess sign determination unit.

[0100] The value when the cam angle is detected within the cam angle signal determination range is set to 1, and when it is further advanced thereafter, it needs to be maintained at 1. On the other hand, when the cam angle is simply detected after being retarded from the initial position, it needs to be maintained at 0. That is, when the cam angle is detected on the retarded angle side from the initial position, the previous value can be maintained.

[0101] Therefore, first, in S1202, it is determined whether the cam angle calculated in S1201 is greater than the cam angle calculated at the initial position. If it is greater, the process proceeds to S1204, and the cam angle signal exceeds the sign judgment value and remains unchanged at the previous value.

[0102] On the other hand, when the cam angle calculated in S1201 is less than the cam angle calculated at the initial position, it is then determined in S1203 whether the cam angle is an angle limited to the cam angle signal judgment range, that is, whether the cam angle is less than the lag angle end of the cam angle signal judgment range angle and greater than the cam angle measurement reference position angle. If it is an angle limited to the cam angle signal judgment range (YES in S1203), the cam angle signal excess sign judgment value is set to 1, and if it is an angle not limited to the cam angle signal judgment range (NO in S1203), it is set to 0.

[0103] (Variation Example)

[0104] Next, use Fig.13A modification of the functional configuration of the operating angle calculation unit will be described.

[0105] Conventionally, the calculation result of the cam angle calculation unit 205 is stored in the cam angle (initial position) storage unit 1301 as the first calculation value after the engine is started. However, since the cam angle at the initial position can also be predetermined by the mounting position relationship between the cam plate 201 or the cam plate 900 and the crank plate 214, the stored value of the cam angle (initial position) storage unit 1301 can also be set to a fixed value.

[0106] Furthermore, the working angle calculation unit (existing formula) 1302 calculates the relationship between the cam angle calculation result and the initial position cam angle by Figure 3 The existing calculation formula (1) described in the above calculation formula calculates the working angle.

[0107] In the present invention, in addition to the existing structure, a basic information storage unit 1303, a conversion cam angle calculation unit 1304, an operating angle calculation unit (conversion cam angle utilization formula) 1305 and an output value selection unit 1306 are newly added.

[0108] The basic information storage unit 1303 stores the following information in advance: Figure 6 The cam angle measurement range is shown in T611. In the cam angle conversion operation unit 1304, as shown in FIG. Figure 6 The cam angle is calculated using the angle of the cam angle measurement range and the cam angle calculation result. In the working angle calculation unit (cam angle conversion formula) 1305, as shown in FIG. Figure 6 As shown, the operating angle is calculated by using the conversion cam angle and the initial position cam angle and the conversion cam angle using equation (2).

[0109] In the output value selection unit 1306, when the switching judgment result calculated by the cam angle exceeding judgment unit 903 is 0, the calculation result of the working angle calculation unit (existing formula) 1302 is output, and when the switching judgment result is 1, the calculation result of the working angle calculation unit (conversion cam angle using formula) 1305 is output.

[0110] use Fig.14 The working angle calculation process is explained.

[0111] Based on the cam angle calculated in S1401, the conversion cam angle is calculated in S1402.

[0112] Next, based on the cam angle calculated in S1401, the operating angle is calculated in S1403 according to the conventional calculation formula (1).

[0113] Next, based on the conversion cam angle calculated in S1402, the operating angle is calculated in S1404 using the conversion cam angle calculation formula (2).

[0114] Finally, based on the cam angle exceeding judgment result, when the cam angle exceeds the measurement reference position angle, the calculation result of S1404 is output as the working angle. When the cam angle does not exceed the measurement reference position angle, the calculation result of S1403 is output as the working angle.

[0115] <Example 2>

[0116] An implementation of a cam angle measuring method according to a second embodiment of the present invention will be described with reference to the drawings.

[0117] The structure of the internal combustion engine including the variable valve mechanism and the structure of the control function related to the conventional working angle calculation are different from those of the embodiment 1. Figure 1 , Figure 2 The description is the same as that of , so it is omitted.

[0118] In the second embodiment, the configuration in which the initial position is set between the most retarded angle position and the most advanced angle position and the control is performed in both the advanced angle direction and the retarded angle direction is described as an example, but the present invention is not limited to this configuration.

[0119] use Fig.15 right Figure 2 The calculation contents of the cam angle calculation unit 205 and the working angle calculation unit 206 are described in detail.

[0120] Fig.15 This is a diagram for explaining a conventional working angle measurement method, with the horizontal axis being time and the vertical axis being the cam angle signal. Fig.15 The upper part of the diagram shows a detection example 1501 of a cam angle signal at an intermediate position. Fig.15 The lower section shows a detection example 1502 of a cam angle signal at a position shifted to the advance angle side and a detection example 1503 of a cam angle signal at a position shifted to the retard angle side.

[0121] Although the cam angle signal also depends on the specifications of the sensor, it is recorded as a specification in which the signal level drops when the detection teeth of the cam angle plate 111 are detected. The times when the ECM detects the cam angle signal are T1521, T1521', and T1521". The time with a dash in the symbol means that the time without a dash in the symbol is the initial position. That is, the time represented by the symbol without a dash is the detection time of the cam angle signal at the middle position, and the time represented by the symbol with a dash is the detection time of the cam angle signal at the advanced angle movement position moving from the middle position to the advanced angle direction or the cam angle signal at the retarded angle movement position moving from the middle position to the retarded angle direction.

[0122] The cam angle signal is also used for cylinder discrimination, but the detection timing changes due to the variable valve mechanism, so the cam angle needs to be detected within a range where the cam angle signal input information (frequency or signal level) does not change. Therefore, the cam angle measurement range T1511 (actually also continues in the right direction) is set to the cylinder phase difference interval (compression TDC interval). For example, in the case of a 3-cylinder internal combustion engine, it becomes a 240degCA interval, and in the case of a 4-cylinder internal combustion engine, it becomes a 180degCA interval.

[0123] As for the cam angle, the advance angle end T1501 (actually continuing to the right) of the cam angle measurement range T1511 is used as the cam angle measurement reference position, and the angle from the advance angle end T1501 to the cam angle signal detection time T1521, T1521', T1521" is detected as the cam angle. For example, within the cam angle measurement range T1511, the angle between the cam angle measurement reference position T1501 and the detection time T321 when the cam angle signal is detected becomes the cam angle (initial position) 1531 at the middle position.

[0124] Furthermore, within the same cam angle measurement range T1511, the angle between the cam angle measurement reference position T1501 and the detection time T1521' at which the cam angle signal is detected becomes the cam angle (operating position) 1532 at the advance angle movement position. Furthermore, the difference between the cam angle (initial position) 1531 and the cam angle (operating position) 1532 is calculated as the operating angle (first operating angle) 1541. This conventional calculation formula is the following formula (1).

[0125] Working angle = cam angle (initial position) - cam angle (working position)... (1)

[0126] In addition, within the same cam angle measurement range T1511, the angle between the cam angle measurement reference position T1501 and the detection time T1521" at which the cam angle signal is detected becomes the cam angle (working position) 1533 at the lag angle movement position. Moreover, the difference between the cam angle (initial position) 1531 and the cam angle (working position) 1533 is calculated as the working angle (first working angle) 1542. This existing calculation formula becomes the above-mentioned formula (1).

[0127] In addition, in the present embodiment, the operating angle at the advanced angle movement position becomes a positive value, and the operating angle at the retarded angle movement position becomes a negative value.

[0128] Next, use Fig.16 The following describes the problems of conventional control when a cam angle plate having a high time resolution and increased detection teeth is applied. Fig.16 This is a diagram for explaining the problems of conventional control.

[0129] For example, the cam angle sensor 202 sets a cam angle measurement range T1601 corresponding to the number of teeth in order to detect a cam angle signal for each tooth of the cam angle plate independently. When a cam angle plate with high time resolution is used, the cam angle measurement range is narrower than when a conventional cam angle plate with a small number of teeth is used.

[0130] However, since the operating range of the variable valve mechanism is determined based on the performance requirements of the internal combustion engine, the same operating range as the existing one is considered. Fig.16 As shown in the upper part of the example where the cam angle signal T1621 is advanced to the position T1621', or the cam angle signal T1621 is delayed to the position T1621", consider the case where the cam angle is detected in the adjacent cam angle measurement range T1610 or T1612 beyond the cam angle measurement range T1611.

[0131] In the example where the cam angle signal T1621 lags to T1621", the cam shaft actually operates in the direction of the lag angle by an operating angle of 1651. However, within the cam angle measurement range T1611 where T1601 is set as the cam angle measurement reference position, the cam angles of T1621 and T1620" are compared and the operating angle 1651' (advanced value) is calculated (incorrect calculation). Fig.16 As shown in the lower part of , although the actual cam angle changes in a manner that gradually increases in the lag angle direction in the range of T1641 to T1647 as shown by the dotted line 1665, in the existing calculation method, the working angle 1666 after exceeding the cam angle measurement reference position angle 1663 (after T1645) is calculated as the advance angle value.

[0132] When this value is fed back, because the advance angle control is excessively performed toward the target angle 1664, the operating range of the variable valve mechanism is limited to the cam angle measurement range and narrowed so as not to exceed the measurement reference position 1663.

[0133] If it is assumed that the cam angle signal T1620” and the cam angle signal T1621” are signals arranged at equal intervals and moving parallel to the circumferential direction of the cam shaft, it can be said that the cam angles of the cam angle signal T1620” and the cam angle signal T1621” are equal. The angle of the cam angle measurement range T1611 is a predetermined value during design, and the working angle 1666 can be calculated based on the cam angles of the cam angle signal T1620” and the cam angle signal T1621 and the angle of the cam angle measurement range T1611.

[0134] Therefore, the cam angle signal T1620" is a signal placed at the initial position within the adjacent cam angle measurement range T1610. If it can be determined that it exceeds the cam angle measurement reference position T1601 and moves in the lag angle direction, the operation method of the working angle is switched.

[0135] Next, use Fig.17 The following describes the method for determining whether to switch the operation angle calculation method. Fig.17 This is a diagram for explaining a range for judging whether there is a sign that the cam angle signal exceeds the cam angle measurement reference position.

[0136] The switching of the working angle calculation formula only requires the recognition of the situation where the cam angle signal exceeds the cam angle measurement reference position. However, it is necessary to distinguish whether the cam angle signal detected in the area exceeding the cam angle measurement reference position is a detection signal formed by advancing or lagging within the cam angle measurement range without exceeding the cam angle measurement reference position. For example, it is necessary to distinguish Fig.17 The cam angle signal T1771" shown is a signal that lags behind T1731 or is a signal that advances the cam angle signal placed in the initial position in the adjacent cam angle measurement range T1712. Therefore, a specified range in the advance angle direction from the cam angle measurement reference position is defined as a cam angle signal lag angle determination range (1701), such as the interval 1702 from T1722 to T1702. When the cam angle changes in the lag angle direction and exceeds the cam angle measurement reference position and moves to other adjacent cam angle measurement ranges, it is determined whether the cam angle measurement reference position is exceeded by using a certain condition of passing through the cam angle signal lag angle determination range.

[0137] When the cam angle changes in the advance angle direction and exceeds the cam angle measurement reference position and moves to another adjacent cam angle measurement range, it is determined whether the cam angle measurement reference position is exceeded by using the fact that the cam angle signal advance angle judgment range has been passed. In addition, the concept of defining the cam angle signal advance angle judgment range is the same as that of defining the cam angle signal lag angle judgment range. Figure 7 The contents are the same as those described in the description.

[0138] That is, after the cam angle signal is detected in the lag angle judgment range, it is judged that the signal detected in the area exceeding the cam angle measurement reference position is a signal based on the lag angle; after the cam angle signal is detected in the advance angle judgment range, it is judged that the signal detected in the area exceeding the cam angle measurement reference position is a signal based on the advance angle, and the calculation formula is switched from the existing formula to calculate the working angle.

[0139] The cam angle signal determination range is set in either angle or time. In this embodiment, it is set in angle for explanation. In addition, the method for determining the width of the cam angle signal determination range is different from that in the above-mentioned embodiment 1. Figure 8 The same idea as described in is confirmed, so the description is omitted.

[0140] Next, based on Fig.18A method for achieving high time resolution measurement without narrowing the operating range of the variable valve mechanism is described. Fig.18 This is a diagram for explaining a method of calculating an operating angle using a signal detected in a region exceeding a cam angle measurement reference position.

[0141] For example, when the camshaft is retarded from the neutral position due to the operation of the variable valve train, such as Fig.18 As shown in the case of moving from cam angle signal T1821 to cam angle signal T1821” from the upper upper section to the upper lower section, the working angle 1851 of the cam angle signal detected at a position exceeding the cam angle measurement range T1811 is composed of the cam angle (initial position) 1831 and the conversion cam angle 1833” from the cam angle measurement reference position T1801 to T1821”.

[0142] The conversion cam angle 1833” is calculated within the cam angle measurement range T1812 based on the cam angle of the cam angle signal T1821” and the angle of the cam angle measurement range T1811, and the above-mentioned cam angle measurement range T1812 becomes the other cam angle measurement range adjacent to the lag angle side relative to the cam angle measurement range T1811. If it is assumed that the cam angle signal T1820” and the cam angle signal T1821” are signals arranged at equal intervals and moving parallel to the circumferential direction of the cam shaft, it can be said that the cam angles of the cam angle signal T1820” and the cam angle signal T1821” are equal, so when the cam angle of the cam angle signal T1820” is the cam angle 1833, the cam angle of the cam angle signal T1821” is also the cam angle 1833. That is, a value obtained by adding the angle of the cam angle measurement range T1811 and the cam angle 1833 becomes a conversion cam angle 1833". This angle is set as the conversion angle of the cam angle 1833, the conversion cam angle 1833".

[0143] Therefore, by subtracting the conversion cam angle 1833″ from the cam angle (initial position) 1831, the accurate working angle (third working angle) 1851 in the retardation angle direction is obtained. The conversion cam angle is calculated using the following calculation formula (3).

[0144] Working angle (when exceeding the hysteresis angle) = cam angle (initial position) - conversion cam angle (working position) ... (3)

[0145] In addition, since the calculation formula when exceeding the advance angle direction becomes the same as Figure 6 Since it is the same as the calculation formula (2) described in , the description thereof will be omitted here.

[0146] exist Fig.18The lower part of the diagram shows the calculation results of the measured angle when the target angles 1861 and 1864 are set in the area exceeding the cam angle measurement reference position angles 1862 and 1863 and the control is started. The vertical axis represents the calculation results of the working angle, and the 0 position represents the cam initial position. In addition, the cam angle measurement reference position angle 1862 is respectively Fig.18 The upper part corresponds to the angle of the cam angle measurement reference position T1801 of the cam angle measurement range T1811. The cam angle measurement reference position angle 1863 is Fig.18 The upper part is the angle corresponding to the cam angle measurement range T1812.

[0147] In order to convert the cam angle detected before exceeding the cam angle measurement reference position angle 1862, 1863 to the working angle, the existing calculation formula (1) is used. Moreover, when converting the cam angle detected after exceeding the cam angle measurement reference position angle 1862, 1863 to the working angle, the calculation formula for obtaining the working angle in the interval T1833 to T1837 is changed from Figure 3 The existing calculation formula (1) described in Figure 6 The conversion cam angle described above is switched using the calculation formula (2), and the calculation formula for the working angle in the interval T1845 to T1850 is changed from Figure 3 The existing calculation formula (1) described in Fig.18 The conversion cam angle described above is switched using the calculation formula (3), thereby being able to calculate the working angle 1866 along the cam shaft motion 1865 without error. Therefore, even in the area where the cam angle exceeds the cam angle measurement reference position angle, high time resolution angle measurement can be achieved.

[0148] By appropriately changing the formula for calculating the working angle in this way, the working angle of the cam can be accurately calculated even in the area where the cam angle exceeds the cam angle measurement reference position. Fig. 9 The same, so the description is omitted.

[0149] Next, the functional structure of the cam angle excess determination unit will be described.

[0150] The cam angle excess judgment unit includes: a cam angle signal advance angle excess sign judgment unit, which judges that the cam angle signal is detected within the cam angle signal advance angle judgment range due to the advance angle of the cam angle; a cam angle signal lag angle judgment unit, which judges that the cam angle signal is detected on the lag angle side than the initial position within the cam angle measurement range; a switching judgment unit A, which indicates switching to the calculation formula (2) used by the working angle calculation unit; a cam angle signal lag angle excess sign judgment unit, which judges that the cam angle signal is detected within the cam angle signal lag angle judgment range due to the lag angle of the cam angle; a cam angle signal advance angle judgment unit, which judges that the cam angle signal is detected on the advance angle side than the initial position within the cam angle measurement range; and a switching judgment unit B, which indicates switching to the calculation formula (3) used by the working angle calculation unit.

[0151] Next, use Fig.19 The timing diagram of the cam angle excess judgment unit is used to illustrate the functions of the cam angle excess judgment unit.

[0152] As an example, the camshaft movement is shown as 1901 in the case where the camshaft is advanced to a target operating angle 1905 exceeding a measurement reference position angle 1906, then delayed to a target operating angle 1910 exceeding a measurement reference position angle 1909, and then returned to an initial position angle of 0 degCA. The operation of the variable valve mechanism starts at T1900, and the cam angle signal is detected at times T1901 to T1923. The operating angle calculation result is shown as 1902.

[0153] In the cam angle signal advance angle excess sign judgment unit, at T1902 when the cam angle signal is detected within the cam angle signal advance angle judgment range 1903, the cam angle signal advance angle excess sign judgment value is set to 1. The previous value is maintained while the cam angle exceeds the measurement reference position angle 1906 and advances. Moreover, when moving from the target working angle 1905 to the retard angle direction, at T1908 when the cam angle is detected within the cam angle signal advance angle judgment range 1903, the cam angle signal excess sign judgment value is set to 1. Because the cam angle signal is detected on the retard angle side of the cam angle signal advance angle judgment range 1903 at T1909, the cam angle signal advance angle excess sign judgment value is set to 0. Next, at T1915, the cam angle signal advance angle excess sign judgment value is set to 1 because the cam angle signal advance angle judgment range is also set on the retard angle side of the measurement reference position angle 1909.

[0154] In the cam angle signal lag angle judgment unit, regardless of the working direction of the cam shaft, when the cam angle calculation unit calculates a value closer to the lag angle side than the initial position, the cam angle signal lag angle judgment value is set to 1. Therefore, T1903 to T1907, T1912 to T1914, and T1920 to T1922 become 1. When the cam angle calculation unit calculates a value closer to the advance angle side than the initial position, the cam angle signal lag angle judgment value is set to 0.

[0155] In the switching judgment unit A, when the cam angle signal advance angle exceeding sign judgment value 1921 is 1 and the cam angle signal lag angle judgment value 1922 is 1, it is judged that the cam angle is a value exceeding the measurement reference position angle 1906, and in order to switch the working angle calculation formula, the switching judgment A value 1923 is set to 1. Therefore, in the interval T1932 from T1903 to T1908, the switching judgment A value is set to 1. Since the conditions are not met in the other intervals T1931 or T1933 to T1935, the switching judgment A value is set to 0.

[0156] In the cam angle signal lag angle excess sign judgment unit, at T1914 when the cam angle signal is detected within the cam angle signal lag angle judgment range 1904, the cam angle signal lag angle excess sign judgment value is set to 1. The previous value is maintained while the cam angle exceeds the measurement reference position angle 1909 and lags. Moreover, when moving from the target working angle 1910 to the advance angle direction, at T1920 when the cam angle is detected within the cam angle signal lag angle judgment range 1904, the cam angle signal excess sign judgment value is set to 1. Because the cam angle signal is detected on the advance angle side than the cam angle signal advance angle judgment range 1904 at T1921, the cam angle signal lag angle excess sign judgment value is set to 0. In addition, at T1912, the cam angle signal lag angle excess sign judgment value is also set to 1 because the cam angle signal lag angle judgment range is also set on the advance angle side of the measurement reference position angle 1906.

[0157] In the cam angle signal advance angle judgment unit, regardless of the working direction of the cam shaft, when the cam angle calculation unit calculates a value closer to the advance angle side than the initial position, the cam angle signal advance angle judgment value is set to 1. Therefore, T1901, T1902, T1908, T1909, T1915 to T1919 become 1. When the cam angle calculation unit calculates a value closer to the retard angle side than the initial position, the cam angle signal advance angle judgment value is set to 0.

[0158] In the switching judgment unit B, when the cam angle signal lag angle exceeding sign judgment value 1924 is 1 and the cam angle signal advance angle judgment value 1925 is 1, it is judged that the cam angle is a value exceeding the measurement reference position angle 1909, and in order to switch the working angle calculation formula, the switching judgment B value 1926 is set to 1. Therefore, in the interval T1934 from T1915 to T1920, the switching judgment B value is set to 1. Since the conditions are not met in the other intervals T1931 to T1933 and T1935, the switching judgment B value is set to 0.

[0159] Next, the control flow of the cam angle signal retardation angle excess sign determination unit will be described.

[0160] The value when the cam angle is detected within the cam angle signal retardation angle determination range is set to 1, and if it further retards, it needs to be maintained at 1. On the other hand, if it is simply detected in advance from the initial position, it needs to be maintained at 0. That is, when the cam angle is detected on the advanced angle side compared to the initial position, the previous value can be maintained.

[0161] Therefore, first, it is determined whether the calculated cam angle is smaller than the cam angle calculated at the initial position. If it is smaller, the cam angle signal lag angle excess sign determination value is kept unchanged from the previous value.

[0162] On the other hand, when the cam angle is greater than the cam angle calculated at the initial position, it is next determined whether the cam angle is an angle limited to the cam angle signal lag angle determination range, that is, whether the cam angle is greater than the advance angle end of the cam angle signal lag angle determination range and less than the maximum angle within the cam angle measurement range. When the angle is limited to the cam angle signal lag angle determination range, the cam angle signal lag angle exceeds the sign judgment value and is set to 1. When the angle is not limited to the cam angle signal lag angle determination range, it is set to 0. In addition, for the cam angle signal advance angle exceeds the sign judgment unit, Fig.12 Omitted from the description.

[0163] (Variation Example)

[0164] Next, a modification of the functional configuration of the operating angle calculation unit will be described.

[0165] Conventionally, the calculation result of the cam angle calculation unit 205 is stored in the cam angle (initial position) storage unit for the first calculation value after the engine is started. However, since the cam angle at the initial position can also be predetermined by the mounting position relationship between the cam plate 201 or the cam plate 900 and the crank plate 214, the stored value of the cam angle (initial position) storage unit can also be set to a fixed value.

[0166] Then, the working angle calculation unit (existing formula) calculates the relationship between the cam angle calculation result and the initial position cam angle by Figure 3 The existing calculation formula (1) described in the calculation of the working angle.

[0167] In the present invention, in addition to the existing structure, a basic information storage unit, an advance angle conversion cam angle calculation unit, an advance angle working angle calculation unit (conversion cam angle utilization formula), a lag angle conversion cam angle calculation unit, a lag angle working angle calculation unit (conversion cam angle utilization formula), and an output value selection unit are newly added. Fig.18 The cam angle measurement range of T1811 is shown in Figure 1. In the advance angle conversion cam angle calculation unit and the lag angle conversion cam angle calculation unit, as shown in Figure 1 Figure 6 or Fig.18 The angle of the cam angle measurement range and the cam angle calculation result are used to calculate the conversion cam angle. In the advance angle working angle calculation unit (conversion cam angle using formula), as Figure 6 As described above, the conversion cam angle calculation formula (2) is used to add the initial position cam angle and the conversion cam angle to calculate the working angle. In the hysteresis angle working angle calculation part (conversion cam angle calculation formula), as Fig.18 As shown, the operating angle is calculated by using the conversion cam angle using equation (3) and subtracting the initial position cam angle and the conversion cam angle.

[0168] In the output value selection unit, when the results of the switching judgment 1 and the switching judgment 2 calculated by the cam angle excess judgment unit are both 0, the calculation result of the working angle calculation unit (conventional formula) is output, when the result of the switching judgment 1 is 1, the calculation result of the advance angle excess working angle calculation unit (conversion cam angle utilization formula) is output, and when the result of the switching judgment 2 is 1, the calculation result of the lag angle excess working angle calculation unit (conversion cam angle utilization formula) is output. In principle, the switching judgment 1 and the switching judgment 2 will not become 1 at the same time, but when they become 1 at the same time, the output value may be used as the calculation result of the working angle calculation unit (conventional formula), or no working angle value may be output.

[0169] The operation angle calculation process is described below. First, the conversion cam angle is calculated based on the cam angle. Next, the operation angle is calculated based on the existing calculation formula (1) based on the cam angle. Next, the operation angle is calculated based on the conversion cam angle using the calculation formulas (2) and (3) respectively.

[0170] Finally, based on the cam angle exceeding judgment result, when the cam angle exceeds the measurement reference position angle in the advance angle direction, the calculation result of the advance angle working angle using the conversion cam angle is output. Moreover, when the cam angle exceeds the measurement reference position angle in the retard angle direction, the calculation result of the retard angle working angle using the conversion cam angle is output. When the cam angle does not exceed the measurement reference position angle in either the advance angle direction or the retard angle direction, the calculation result of the working angle calculation (existing formula) is output as the working angle.

[0171] The control device of the present invention (1) is a control device for controlling a variable valve mechanism of an internal combustion engine based on a crank angle signal and a cam angle signal, and is characterized in that it comprises: a working angle calculation unit, which calculates an initial cam angle based on an interval between a cam angle measurement reference position in a cam angle measurement range and an initial cam angle signal detection position at an initial position of the variable valve mechanism, calculates a working cam angle based on an interval between a cam angle measurement reference position in the cam angle measurement range and a working cam angle signal detection position at a working position of the variable valve mechanism, and calculates the working angle of the variable valve mechanism based on a difference between the initial cam angle and the working cam angle; and when the cam angle exceeds A judging unit, which judges whether the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range through the operation of the variable valve mechanism. When the cam angle exceeds the judging unit, it is judged that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range, the working angle calculation unit calculates the working angle based on the initial cam angle at the initial position of the variable valve mechanism and the working cam angle of the other cam angle measurement range at the working position of the variable valve mechanism.

[0172] The control device of the present invention (2) is characterized in that the cam angle exceeding judgment unit includes: a cam angle signal exceeding sign judgment unit, which judges whether the cam angle signal is detected within the cam angle signal judgment range, and the cam angle signal judgment range is set as a range within the cam angle measurement range in which the working cam angle signal detection position passes through the lag angle side of the cam angle measurement reference position due to the operation of the variable valve mechanism; a cam angle signal lag angle judgment unit, which judges whether the cam angle signal is detected within the cam angle measurement range on the lag angle side than the initial cam angle signal detection position. When the cam angle signal exceeding sign judgment unit judges that the cam angle signal is detected within the cam angle signal judgment range, and then the cam angle signal lag angle judgment unit judges that the cam angle signal is detected within the cam angle measurement range on the lag angle side than the initial cam angle signal detection position, it is judged that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range.

[0173] The control device of the present invention (3) is characterized in that the cam angle excess judgment unit includes: a cam angle signal advance angle excess sign judgment unit, which judges whether the cam angle signal is detected within a cam angle signal advance angle judgment range, and the cam angle signal advance angle judgment range is set as a range within the cam angle measurement range where the working cam angle signal detection position passes through the lag angle side of the cam angle measurement reference position due to the operation of the variable valve mechanism; and

[0174] a cam angle signal retardation angle determination unit for determining whether the cam angle signal is detected at a retardation angle side relative to an initial cam angle signal detection position within the cam angle measurement range,

[0175] When the cam angle signal advance angle excess sign judgment unit determines that the cam angle signal is detected within the cam angle signal advance angle judgment range, and then the cam angle signal lag angle judgment unit determines that the cam angle signal is detected within the cam angle measurement range at a lag angle side relative to the initial cam angle signal detection position, it is determined that the operating cam angle signal detection position exceeds the cam angle measurement reference position and moves to another cam angle measurement range adjacent to the cam angle measurement range.

[0176] Alternatively, it comprises: a cam angle signal lag angle exceeding sign judging unit, which judges whether the cam angle signal is detected within a cam angle signal lag angle judging range, wherein the cam angle signal lag angle judging range is set as a range within the cam angle measurement range where the working cam angle signal detection position passes through the advance angle side of the cam angle measurement reference position due to the operation of the variable valve mechanism; and

[0177] a cam angle signal advance angle determination unit for determining whether the cam angle signal is detected at an advance angle side relative to an initial cam angle signal detection position within the cam angle measurement range,

[0178] When the cam angle signal lag angle exceeds the sign judgment unit determines that the cam angle signal is detected within the cam angle signal lag angle judgment range, and then the cam angle signal advance angle judgment unit determines that the cam angle signal is detected on the advance angle side of the initial cam angle signal detection position within the cam angle measurement range, it is determined that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range.

[0179] The control device of the present invention (4) is characterized in that the cam angle measurement reference position is set at one or more places at 720deg crank angle (degCA) based on the crank angle signal, the cam angle measurement range has an interval greater than the interval of inputting the cam angle signal in the lag angle direction relative to the cam angle measurement reference position, and the cam angle signal judgment range has a width synchronized with the input speed of the cam angle signal.

[0180] The control device of the present invention (5) is characterized in that the cam angle signal judgment range is set from the advance angle end or the lag angle end of the cam angle measurement range or each of its two ends within any range within a specified angle range or time range.

[0181] The control device of the present invention (6) is characterized in that the specified angle range or time range of the cam angle signal judgment range is based on the working speed of the variable valve mechanism and the cam angle signal input period or engine speed, and the range of the cam angle signal that must be detected more than once is set.

[0182] The control device of the present invention (7) is characterized in that, with respect to the working angle calculation unit, the first working angle is calculated based on the difference between the initial cam angle and the working cam angle, the second working angle is calculated based on the sum of the initial cam angle and the converted cam angle for converting the working cam angle at the working position of the variable valve into an advance angle direction value, the third working angle is calculated based on the difference between the initial cam angle and the cam angle for converting the working cam angle at the working position of the variable valve into a retard angle direction value, the third working angle is calculated based on the difference between the initial cam angle and the cam angle for returning the working cam angle at the working position of the variable valve to a retard angle direction value, and when the cam angle exceeds the judgment unit and it is not judged that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range, the first working angle is output, and when it is judged that it moves to, the second working angle is output.

[0183] In addition, the present invention is not limited to the above-mentioned embodiments. In addition, control lines or information lines are shown in the description as necessary, and not all control lines or information lines are necessarily shown on the product. In fact, it can also be considered that almost all structures are connected to each other.

[0184] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various design changes can be made within the scope of the spirit of the present invention as described in the claims. For example, the above embodiments are described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to all structures included in the description. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and in addition, the structure of other embodiments can be added to the structure of a certain embodiment. Moreover, other structures can be added, deleted, or replaced with a part of the structure of each embodiment.

[0185] Description of Reference Numerals

[0186] 1101 Actual camshaft operating angle

[0187] 1102 Working angle calculation result

[0188] 1103 Cam angle signal judgment range

[0189] 1104 Target working angle

[0190] 1105 Measurement reference position relative to the initial position (working angle 0degCA)

[0191] 1106 Cam angle signal judgment range lag angle end

[0192] 1121 Cam angle signal exceeds the sign judgment

[0193] 1122 Cam angle signal hysteresis angle judgment

[0194] 1123 Switch judgment

[0195] T1100 variable valve mechanism working start time

[0196] T1101~T1121 Cam angle signal detection time after the variable valve mechanism starts working

[0197] T1131 and T1133 use the existing working angle calculation formula to calculate the working angle area

[0198] T1132 calculates the range of the operating angle by using the operating angle calculation formula for converting the cam angle.

Claims

1. A control device for controlling a variable valve mechanism of an internal combustion engine based on a crank angle signal and a cam angle signal, the control device comprising: a working angle calculation unit that calculates an initial cam angle based on an interval between a cam angle measurement reference position in a cam angle measurement range and an initial cam angle signal detection position at an initial position of the variable valve mechanism, calculates a working cam angle based on an interval between a cam angle measurement reference position in the cam angle measurement range and a working cam angle signal detection position at a working position of the variable valve mechanism, and calculates a working angle of the variable valve mechanism based on a difference between the initial cam angle and the working cam angle; and a cam angle exceeding judgment unit for judging whether the operating cam angle signal detection position exceeds the cam angle measurement reference position and moves to another cam angle measurement range adjacent to the cam angle measurement range due to the operation of the variable valve mechanism, When the cam angle exceeding judgment unit determines that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range, the working angle calculation unit calculates the working angle based on the initial cam angle at the initial position of the variable valve mechanism and the working cam angle of the other cam angle measurement ranges at the working position of the variable valve mechanism.

2. The control device according to claim 1, characterized in that: The cam angle exceeding judgment unit comprises: a cam angle signal exceeding sign judging section for judging whether the cam angle signal is detected within a cam angle signal judging range, the cam angle signal judging range being set as a range within the cam angle measurement range where the operating cam angle signal detection position passes through a lag angle side of the cam angle measurement reference position due to the operation of the variable valve mechanism; and a cam angle signal retardation angle determination unit for determining whether the cam angle signal is detected at a retardation angle side relative to an initial cam angle signal detection position within the cam angle measurement range, When the cam angle signal exceeds the sign judgment unit and determines that the cam angle signal is detected within the cam angle signal judgment range, and then the cam angle signal lag angle judgment unit determines that the cam angle signal is detected within the cam angle measurement range on the lag angle side relative to the initial cam angle signal detection position, it is determined that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range.

3. The control device according to claim 1, characterized in that: The cam angle exceeding judgment unit comprises: a cam angle signal advance angle excess sign judging section for judging whether the cam angle signal is detected within a cam angle signal advance angle judging range, the cam angle signal advance angle judging range being set as a range within the cam angle measurement range where the operating cam angle signal detection position passes through a lag angle side of the cam angle measurement reference position due to the operation of the variable valve mechanism; and a cam angle signal retardation angle determination unit for determining whether the cam angle signal is detected at a retardation angle side relative to an initial cam angle signal detection position within the cam angle measurement range, When the cam angle signal advance angle exceeding sign judgment unit determines that the cam angle signal is detected within the cam angle signal advance angle judgment range, and then the cam angle signal lag angle judgment unit determines that the cam angle signal is detected within the cam angle measurement range at a lag angle side relative to the initial cam angle signal detection position, it is determined that the operating cam angle signal detection position exceeds the cam angle measurement reference position and moves to another cam angle measurement range adjacent to the cam angle measurement range. Alternatively, the cam angle exceeding judgment unit includes: a cam angle signal lag angle exceeding sign judging section for judging whether the cam angle signal is detected within a cam angle signal lag angle judging range, the cam angle signal lag angle judging range being set as a range within the cam angle measuring range where the operating cam angle signal detection position passes through the advance angle side of the cam angle measurement reference position due to the operation of the variable valve mechanism; and a cam angle signal advance angle determination unit for determining whether the cam angle signal is detected at an advance angle side relative to an initial cam angle signal detection position within the cam angle measurement range, When the cam angle signal lag angle exceeds the sign judgment unit determines that the cam angle signal is detected within the cam angle signal lag angle judgment range, and then the cam angle signal advance angle judgment unit determines that the cam angle signal is detected on the advance angle side of the initial cam angle signal detection position within the cam angle measurement range, it is determined that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range.

4. The control device according to claim 2, characterized in that: The cam angle measurement reference position is set at one or more positions within 720 degrees crank angle (degCA) based on the crank angle signal. The cam angle measurement range has an interval greater than an interval at which the cam angle signal is input in a retarded angle direction relative to the cam angle measurement reference position. The cam angle signal determination range has a width synchronized with an input speed of the cam angle signal.

5. The control device according to claim 2, characterized in that: The cam angle signal determination range is set in any range of a prescribed angle range or a time range from an advance angle end or a retard angle end of the cam angle measurement range or each of both ends thereof.

6. The control device according to claim 5, characterized in that: The specified angle range or time range of the cam angle signal judgment range is based on the operating speed of the variable valve mechanism and the cam angle signal input cycle or the engine speed, and sets the range in which the cam angle signal must be detected more than once.

7. The control device according to claim 2 or 3, characterized in that: The working angle calculation unit, calculating a first working angle according to the difference between the initial cam angle and the working cam angle, a second working angle is calculated based on the sum of the initial cam angle and the conversion cam angle obtained by converting the working cam angle at the working position of the variable valve mechanism into an advance angle direction value, and a third working angle is calculated based on the difference between the initial cam angle and the cam angle obtained by converting the working cam angle at the working position of the variable valve mechanism into a retard angle direction value, When the cam angle exceeding judgment unit does not judge that the working cam angle signal detection position exceeds the cam angle measurement reference position and moves to other cam angle measurement ranges adjacent to the cam angle measurement range, the first working angle is output; when it is judged that it has moved to, the second working angle or the third working angle is output.

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