JP4576303B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve operating apparatus for an internal combustion engine that changes the lift of an intake valve of the internal combustion engine in a stepless manner, and more particularly to a failure determination apparatus that determines a failure of a lift detection means that detects lift of the intake valve.

  As a conventional valve operating device for this type of internal combustion engine, for example, one disclosed in Patent Document 1 is known. The valve operating apparatus includes a cam shaft, a swing cam that is rotatably supported by the cam shaft, and that drives the intake valve to open and close, a rotatable control shaft, and a link that connects the swing cam and the control shaft to each other. And an actuator for rotating the control shaft, an operating angle sensor for detecting the operating angle of the control shaft, and the like. In this valve operating apparatus, after determining the target lift of the intake valve according to the detected rotational speed of the internal combustion engine, the intake air amount, etc., the target operating angle of the control shaft is calculated based on the determined target lift. Then, by rotating the control shaft with the actuator so that the operating angle of the control shaft detected by the operating angle sensor becomes the target operating angle, the swing cam is rotated and the lift of the intake valve is changed steplessly. .

  Moreover, in this patent document 1, the failure determination of an operating angle sensor is performed as follows. First, as an execution condition for the failure determination, it is determined whether or not the operating state of the internal combustion engine is almost a steady state. In this determination, regarding the detected rotational speed of the internal combustion engine, the intake air amount, and the opening of the throttle valve (hereinafter referred to as “throttle opening”), the deviation between the current value and the value before the predetermined time is the respective difference. When the absolute value of the difference between the throttle opening calculated based on the rotational speed of the internal combustion engine and the intake air amount and the detected throttle opening is less than the predetermined value, the internal combustion engine is almost in a steady state. It is determined that When the internal combustion engine is in a substantially steady state, when the difference between the target operating angle of the control shaft calculated as described above and the operating angle detected by the operating angle sensor is equal to or greater than a predetermined value, the operating angle sensor Determine that there is a failure.

  However, in the above-described conventional valve operating apparatus for an internal combustion engine, the failure determination of the operating angle sensor is performed on the condition that the operation state of the internal combustion engine is almost steady, that is, the rotational speed of the internal combustion engine, the intake air amount and the throttle A very limited condition in which the difference between the current value of the opening and the value before the predetermined time is all less than the predetermined value, and the difference between the calculated throttle opening and the detected throttle opening is less than the predetermined value Then it is executed. For this reason, failure determination cannot be performed if any of the engine speed, intake air amount, and throttle opening change exceeds a predetermined value, as well as in an overrun state such as during acceleration or deceleration. There is a problem that sufficient execution opportunities for failure determination cannot be secured.

  The present invention has been made to solve such a problem, and appropriately determines the failure determination of the lift detection means for detecting the lift of the intake valve in the valve operating apparatus while sufficiently securing the execution opportunity. An object of the present invention is to provide a valve operating device for an internal combustion engine that can be performed.

JP 2000-282901 A

  In order to achieve this object, the invention according to claim 1 is a variable intake lift mechanism 70 capable of steplessly changing the lift of the intake valve 4 of the internal combustion engine 3 and a target lift of the intake valve 4 (in the embodiment ( Hereinafter, the same in this section) Target lift setting means (ECU 2, step 1 in FIG. 5) for setting the target rotation angle SACMD) and lift detection for detecting the lift of the intake valve 4 as an actual lift (rotation angle SAAIN) Means (lift sensor 20), lift control means (actuator 80, ECU 2, step 2) for controlling the intake lift variable mechanism 70 so that the actual lift of the intake valve 4 becomes the target lift, and the rotational speed ( A rotational speed detection means (crank angle sensor 21, ECU 2) for detecting the engine rotational speed NE), one of the actual lift and the target lift of the intake valve 4 and the detected rotational speed; Correspondingly, intake air amount estimating means (ECU 2, step 14 in FIG. 6) for estimating the amount of intake air sucked into the cylinder 3a of the internal combustion engine 3 (estimated intake air amount QES), and the intake sucked into the cylinder 3a Whether the actual lift has converged to the target lift by comparing the actual lift of the intake valve 4 and the target lift with the intake air amount detection means (air flow sensor 22) for detecting the amount of air (intake air amount QA). When the determination means (ECU 2, step 13) determines that the actual lift of the intake valve 4 has converged to the target lift, the estimated intake air amount and the detected intake air are determined. Failure determination means (ECU 2, steps 13 to 18) for determining that the lift detection means has failed when the deviation from the amount (| QES−QA |) is equal to or greater than a predetermined value (predetermined amount QLMT). Characterized in that it comprises a and.

  According to this valve operating apparatus for an internal combustion engine, the lift of the intake valve of the internal combustion engine is changed steplessly by the intake lift variable mechanism, and the lift detection means detects the lift of the intake valve as an actual lift. The target lift setting means sets the target lift of the intake valve, and the lift control means controls the intake lift variable mechanism so that the actual lift of the intake valve becomes the target lift. As a result, an amount of air corresponding to the lift is sucked into the cylinder of the internal combustion engine, and the amount of the sucked intake air is detected by the intake air amount detection means. The intake air amount estimation means estimates the amount of intake air that is taken into the cylinder according to the detected number of revolutions of the internal combustion engine as one of the actual lift and the target lift of the intake valve. The determination means determines whether or not the actual lift has converged to the target lift by comparing the actual lift of the intake valve and the target lift. Further, the failure determination means determines that the lift is detected when the deviation between the estimated intake air amount and the detected intake air amount is equal to or greater than a predetermined value when it is determined that the actual lift of the intake valve has converged to the target lift. It is determined that the detection means has failed.

  When the lift of the intake valve is variable, the amount of intake air actually sucked into the internal combustion engine greatly depends on the lift of the intake valve and the rotational speed of the internal combustion engine. For this reason, in the state where the actual lift of the intake valve converges to the target lift, the intake air amount estimated according to one of the actual lift and target lift of the intake valve and the rotation speed of the internal combustion engine is correct. If this is the case, the detected actual intake air amount should almost coincide. Therefore, when the deviation between the estimated intake air amount and the detected intake air amount is greater than or equal to a predetermined value and the difference between the two is large, it is determined that the actual lift is not correct and the lift detection means for detecting this is malfunctioning. be able to. Thus, the failure determination can be appropriately performed by comparing the estimated intake air amount with the actual intake air amount.

  Moreover, since the failure determination is executed on the condition that the actual lift has converged to the target lift, the failure determination can be executed regardless of the operating state of the internal combustion engine as long as such a condition is satisfied. . For this reason, unlike the above-described conventional valve gear, failure determination can be performed not only when the operating state of the internal combustion engine is almost steady, but also during an excessive operating state such as during acceleration or deceleration. Sufficient execution opportunities can be secured.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a valve gear 1 according to an embodiment of the present invention and an internal combustion engine (hereinafter referred to as “engine”) 3 to which the valve operating device 1 is applied. The engine 3 is an in-line four-cylinder gasoline engine having four cylinders 3a (only one is shown), and is mounted on a vehicle (not shown). A combustion chamber 3e is formed between the piston 3b and the cylinder head 3c of each cylinder 3a.

  The engine 3 is integrated with a pair of intake valves 4 and 4 and a pair of exhaust valves 7 and 7 (only one is shown), an intake camshaft 5 on the intake side, and the intake camshaft 5 provided for each cylinder 3a. , An exhaust camshaft 8 on the exhaust side, an exhaust cam 9 integrally attached to the exhaust camshaft 8, a fuel injection valve 10 (see FIG. 2), and a spark plug 11 (see FIG. 2). And a variable intake lift mechanism 70 and the like.

  Each of the intake camshaft 5 and the exhaust camshaft 8 is rotatably supported by the cylinder head 3c via a holder (not shown), and extends along the arrangement direction of the cylinders 3a. The intake camshaft 5 is connected to the crankshaft 3d via a timing chain (not shown). With this configuration, the intake camshaft 5 rotates once every time the crankshaft 3d rotates twice, and the intake valve 4 is driven to open and close by the rotation of the intake cam 6 accompanying this rotation.

  Similarly, the exhaust camshaft 8 is connected to the crankshaft 3d via a timing chain (not shown), and rotates once for every two rotations of the crankshaft 3d. Thus, the exhaust valve 7 is driven to open and close.

  On the other hand, the fuel injection valve 10 is provided for each cylinder 3a, and is attached to the cylinder head 3c so as to inject fuel directly into the cylinder 3a. The valve opening time and the valve opening timing of the fuel injection valve 10 are controlled by a drive signal from the ECU 2, thereby controlling the fuel injection amount and the injection timing.

  A spark plug 11 is also provided for each cylinder 3a and attached to the cylinder head 3c. The discharge state of the spark plug 11 is controlled by the ECU 2 so that the air-fuel mixture in the combustion chamber 3e is combusted at a timing corresponding to the ignition timing.

  The intake lift variable mechanism 70 is for changing the lift of the intake valve 4 (hereinafter referred to as “intake lift”) steplessly between a value of 0 and a predetermined maximum value. 3 and 4, the variable intake lift mechanism 70 includes a control shaft 71 and a rocker arm shaft 72, upper and lower rocker arms 74 and 75 provided on the shafts 71 and 72 for each cylinder 3a, Actuators 80 for driving the upper and lower rocker arms 74 and 75 are provided. In the present embodiment, the intake lift represents the maximum lift of the intake valve 4.

  The control shaft 71 is an assembly of a rotating shaft portion 71a, a holder portion 71b, and an eccentric shaft portion 71c. The control shaft 71 extends along the intake camshaft 5 and is rotatably supported by the cylinder head 3c. One end thereof is connected to the actuator 80.

  The upper rocker arm 74 includes a pair of links 74a and 74a, a roller shaft 74b, a roller 74c, and a pair of coil springs 74d and 74d. The roller shaft 74b is rotatably supported at one end of the links 74a and 74a at both ends thereof. The roller 74c is rotatably provided on the roller shaft 74b.

  The other end of each link 74a is rotatably supported by the eccentric shaft portion 71c of the control shaft 71, and is connected to the holder portion 71b via a coil spring 74d. In the link 74a, when the roller 74c is in contact with the cam surface of the intake cam 6 and the roller 74c is in contact with the base circle portion of the cam surface of the intake cam 6 by the biasing force of the coil spring 74d, the roller shaft 74b is held at an origin position (position shown in FIG. 3) coaxial with the rotation shaft portion 71a.

  On the other hand, the lower rocker arm 75 is rotatably supported by the rocker arm shaft 72 at one end portion thereof, and adjustment bolts 75a and 75a are attached to the other end portion thereof. It is in contact with the upper end of the intake valve 4.

  The lower rocker arm 75 includes a pair of guide portions 75b and 75b protruding upward. The upper surface of each guide portion 75b serves as a guide surface 75c for guiding the roller shaft 74b of the upper rocker arm 74, and is in contact with the roller shaft 74b via the guide surface 75c. The guide surface 75c is formed in a predetermined arc shape protruding downward so as to be concentric with the eccentric shaft portion 71c when the link 74a is in the valve closing position shown by the solid line in FIG. Further, in a state where the guide portion 75b and the roller shaft 74b are in contact with each other, the roller 74c is positioned between the guide portions 75b and 75b and contacts only the intake cam 6 without contacting the lower rocker arm 75.

  On the other hand, the actuator 80 is a combination of a motor, a reduction gear mechanism (both not shown) and the like, and is driven by the ECU 2 to rotate the control shaft 71 around the rotation shaft portion 71a. . As the control shaft 71 rotates, the link 74a also rotates about the roller shaft 74b.

  Next, the operation of the variable intake lift mechanism 70 configured as described above will be described. In the intake lift variable mechanism 70, when the actuator 80 is driven by the drive signal from the ECU 2, the control shaft 71 rotates. At this time, the rotation angle SAAIN of the control shaft 71 is restricted within a predetermined range, and accordingly, the rotation range of the link 74a is also zero lift indicated by a solid line in FIG. 3, for example, when the roller shaft 74b is at the aforementioned origin position. It is regulated between the position and the maximum lift position indicated by a two-dot chain line.

  When the link 74a is in the zero lift position as described above, the intake cam 6 rotates, and when the roller nose 74c is pushed toward the rocker arm shaft 72 by the cam nose, the link 74a rotates clockwise in FIG. 3 about the eccentric shaft portion 71c. To turn. At this time, as described above, since the guide surface 75c of the lower rocker arm 75 has a shape that coincides with an arc centered on the eccentric shaft portion 71c, the lower rocker arm 75 has a valve closing position shown in FIG. Retained. As a result, the intake lift is maintained at a value of 0, and the intake valve 4 is maintained in a closed state.

  On the other hand, in a state where the link 74a is rotated from the zero lift position to the maximum lift position, the link 74a is rotated about the eccentric shaft portion 71c in the clockwise direction in FIG. The rocker arm 75 rotates downward from the valve closing position shown in FIG. 3 to open the intake valve 4. At that time, the rotation amount of the lower rocker arm 75, that is, the intake lift becomes larger as the link 74a is closer to the maximum lift position.

  As described above, in this intake lift variable mechanism 70, the link 74a is rotated between the zero lift position and the maximum lift position via the actuator 80, whereby the intake lift is set to a value between 0 and a predetermined maximum value. Can be changed steplessly between.

  The intake lift variable mechanism 70 is provided with a lift sensor 20 (lift detection means) for detecting intake lift (see FIG. 2). The lift sensor 20 detects the rotation angle SAAIN of the control shaft 71 and outputs a detection signal representing it to the ECU 2. As described above, since the intake lift is uniquely determined from the rotation angle SAAIN of the control shaft 71, the detected rotation angle SAAIN represents an actual intake lift (actual lift).

  On the other hand, the engine 3 is provided with a crank angle sensor 21. The crank angle sensor 21 includes a magnet rotor and an MRE pickup, and outputs a CRK signal and a TDC signal, which are pulse signals, to the ECU 2 as the crankshaft 3d rotates.

  The CRK signal is output every predetermined crank angle (for example, 10 °), and the ECU 2 calculates the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal. The TDC signal is a signal indicating that the piston 3b of each cylinder 3a is at a predetermined crank angle position slightly before the TDC position of the intake stroke, and is output at every predetermined crank angle.

  The intake pipe 12 of the engine 3 is provided with an air flow sensor 22 (intake air amount detection means). The air flow sensor 22 detects the intake air amount QA, and the detection signal is output to the ECU 2. Further, a detection signal representing an operation amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown) is output from the accelerator opening sensor 23 to the ECU 2.

  The ECU 2 (target lift setting means, lift control means, rotation speed detection means, intake air amount estimation means, determination means and failure determination means) is constituted by a microcomputer comprising an I / O interface, CPU, RAM and ROM. ing. The detection signals from the various sensors 20 to 23 described above are each output to the CPU after A / D conversion and shaping by the I / O interface.

  In accordance with these input signals, the CPU determines the operating state of the engine 3 according to a control program stored in the ROM and the like, and controls the intake lift according to the determined operating state. Moreover, the failure sensor 20 failure determination process is executed.

  FIG. 5 is a flowchart showing an intake lift control process. This process is executed in synchronization with the generation of the TDC signal. In this process, in step 1 (illustrated as “S1”, the same applies hereinafter), a predetermined map (not shown) is searched according to the accelerator pedal opening AP and the engine speed NE, so that the intake lift variable mechanism 70 A target rotation angle SACMD of the control shaft 71 is set. This target rotation angle SACMD corresponds to the target lift of the intake valve 4. Next, based on the target rotation angle SACMD and the rotation angle SAAIN of the control shaft 71 detected by the lift sensor 20, a control input U_SAAIN for controlling the intake lift variable mechanism 70 is calculated (step 2). This process ends. The control input U_SAAIN is calculated by a predetermined feedback control algorithm so that the rotation angle SAAIN converges to the target rotation angle SACMD. Then, by outputting a drive signal based on the calculated control input U_SAAIN to the intake lift variable mechanism 70, the actual intake lift is controlled to become the target lift.

  FIG. 6 is a flowchart showing a failure determination process of the lift sensor 20. This process is executed every predetermined time. In this process, in step 11, it is determined whether all of the crank angle sensor 21, the airflow sensor 22, and the accelerator opening sensor 23 are operating normally. When the determination result is NO and any of these various sensors 21 to 23 is not normal, the timer value TM of a down-counting timer (not shown) is set to a predetermined value TMREF (for example, 5 seconds) ( After step 12), the process is terminated.

  On the other hand, when the determination result in step 11 is YES, it is determined whether or not the absolute value (= | SACMD−SAAIN |) of the difference between the target rotation angle SACMD and the rotation angle SAAIN is equal to or less than a predetermined value SALMT. (Step 13). When the determination result is NO, assuming that the intake lift has not converged to the target lift and the amount of intake air sucked into the cylinder 3a is not stable, step 12 is executed, and this process is terminated.

  On the other hand, if the determination result in step 13 is YES and | SACMD−SAAIN | ≦ SALMT, it is assumed that the actual intake lift has converged to the target lift and the intake air amount is in a stable state. QES is calculated (step 14). This estimated intake air amount QES is an intake air amount estimated to be sucked into the cylinder 3a, and by searching a predetermined map (not shown) based on the engine speed NE and the rotation angle SAAIN, Calculated.

  Next, the absolute value (= | QES−QA |) of the difference between the estimated intake air amount QES calculated in step 14 and the intake air amount QA detected by the air flow sensor 22 is calculated as an intake air amount deviation ΔQ ( Step 15), it is determined whether or not the intake air amount deviation ΔQ is equal to or greater than a predetermined amount QLMT (predetermined value) (Step 16). When the determination result is NO and the intake air amount deviation ΔQ is smaller than the predetermined amount QLMT, it is determined that the lift sensor 20 has not failed, step 12 is executed, and this process is terminated.

  On the other hand, if the determination result in step 16 is YES and the intake air amount deviation ΔQ is equal to or greater than the predetermined amount QLMT, it is determined whether or not the timer value TM is 0 (step 17). When this determination result is NO, this process is terminated as it is. On the other hand, when the determination result in step 17 is YES and the timer value TM is 0, that is, the state where the intake air amount deviation ΔQ is equal to or greater than the predetermined amount QLMT continues for a predetermined time, the actual intake air amount QA is The estimated intake air amount QES calculated on the basis of the detected rotation angle SAAIN and the engine speed NE should be substantially equal to the estimated intake air amount QES. However, since this is not the case, the lift sensor 20 is broken. judge. In order to express this, the lift sensor failure flag F_SLIFTNG is set to “1” (step 18), and this process is terminated.

  FIG. 7 is a timing chart showing an example of determination of failure of the lift sensor 20 by the processing of FIG. This example shows a case where a failure occurs in which the detected value from the lift sensor 20 shifts to the increasing side with respect to the true value at the timing t1. Before t1, the detected rotation angle SAAIN is controlled to be the target rotation angle SACMD by the intake lift control of FIG. Further, since the lift sensor 20 is normal, the estimated intake air amount QES calculated according to the rotation angle SAAIN and the engine speed NE is substantially equal to the detected intake air amount QA.

  Further, even after t1 when the lift sensor 20 fails as described above, the apparent rotation angle SAAIN detected by the intake lift control of FIG. Control is made so that the dynamic angle SACMD is obtained. However, actually, since the detected rotation angle SAAIN is shifted to the increasing side, the actual rotation angle is controlled to be smaller than the target rotation angle SACMD, and accordingly, the actual intake air amount QA is , Shift to the smaller side. As a result, the estimated intake air amount QES calculated according to the detected apparent rotation angle SAAIN and the engine speed NE does not coincide with the intake air amount QA actually detected by the air flow sensor 22 and exceeds this. As a result, the intake air amount deviation ΔQ, which is the difference between the two, gradually increases. When the intake air amount QA becomes equal to or greater than the predetermined amount QLMT (t2), the timer starts, and when the state continues for a time corresponding to the predetermined value TMREF, the timer value TM becomes the value 0 (t3). ), It is determined that the lift sensor 20 is malfunctioning.

  Contrary to the above, when a failure occurs in which the detection value of the lift sensor 20 deviates from the true value, the estimated intake air amount QES becomes lower than the intake air amount QA. Failure determination can be performed in the same manner.

  As described above, according to the present embodiment, the variable intake lift mechanism 70 is controlled so that the detected rotation angle SAAIN becomes the target rotation angle SACMD. The absolute value of the difference between the target rotation angle SACMD and the rotation angle SAAIN is equal to or smaller than the predetermined value SALMT, that is, in a state where the rotation angle SAAIN converges to the target rotation angle SACMD, the rotation angle SAAIN and the engine speed NE The intake air amount deviation ΔQ, which is the absolute value of the difference between the estimated intake air amount QES and the intake air amount QA, is compared with a predetermined amount QLMT. Make a decision. As described above, when the rotation angle SAAIN converges to the target rotation angle SACMD, the intake air amount QA should substantially match the estimated intake air amount QES if the lift sensor 20 is not malfunctioning. Therefore, when the intake air amount deviation ΔQ is equal to or greater than the predetermined amount QLMT, it can be appropriately determined that the lift sensor 20 is malfunctioning.

  Further, since the failure determination is executed on condition that the absolute value of the difference between the target rotation angle SACMD and the rotation angle SAAIN is equal to or smaller than the predetermined value SALMT, the operation of the engine 3 is performed as long as such a condition is satisfied. Failure determination can be executed regardless of the state. For this reason, since the failure determination can be executed not only when the engine 3 is in a substantially steady state but also in an excessive operation state such as acceleration or deceleration, a sufficient execution opportunity can be ensured.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the estimated intake air amount QES is obtained according to the rotation angle SAAIN and the engine speed NE, but the target rotation angle SACMD may be used instead of the rotation angle SAAIN. In addition, other parameters that affect the actual intake air amount may be taken into account.For example, when a throttle valve is provided in the intake pipe, the estimated intake air amount is further determined according to the throttle opening. It may be calculated. Furthermore, in the embodiment, the lift sensor 20 that detects the rotation angle SAAIN of the control shaft 71 is used as the lift detection means. However, the present invention is not limited to this. For example, a sensor that directly detects the intake lift may be used. . In addition, the intake lift may be estimated using an appropriate parameter highly related to the intake lift. Furthermore, in the embodiment, whether or not the actual lift has converged to the target lift is determined using the absolute value of the difference between the target rotation angle SACMD and the rotation angle SAAIN, but is not limited thereto. For example, the ratio between the two may be used, and when the ratio is approximately 1.0, it may be determined that the intake lift has converged to the target lift. In the embodiment, the deviation between the estimated intake air amount QES and the intake air amount QA is the intake air amount deviation ΔQ, which is the absolute value of the difference between the two. It may be used.

  In the embodiment, the target rotation angle SACMD is calculated according to the accelerator opening AP and the engine speed NE. For example, the required torque is obtained from the accelerator opening AP and the engine speed NE, The calculation may be performed according to the required torque and the engine speed NE, and the calculation method is arbitrary. Furthermore, the variable intake lift mechanism 70 is not limited to the type exemplified in the embodiment, and any type can be adopted as long as the lift of the intake valve can be changed steplessly.

  Furthermore, although embodiment is an example which applied this invention to the gasoline engine, this invention is not restricted to this, Various engines other than a gasoline engine, for example, a diesel engine and a crankshaft, are arrange | positioned in the perpendicular direction. The present invention can be applied to a marine vessel propulsion engine such as an outboard motor. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

It is a figure which shows schematic structure of the valve operating apparatus of this invention, and the internal combustion engine to which this is applied. It is a figure which shows a part of valve operating apparatus. It is a schematic diagram which shows schematic structure of an intake lift variable mechanism. It is a perspective view which shows schematic structure of an intake lift variable mechanism. It is a flowchart which shows the control processing of intake lift. It is a flowchart which shows the process which determines the failure of the lift sensor of the valve gear of FIG. It is a timing chart which shows the example of judgment of failure of a lift sensor.

Explanation of symbols

1 valve gear 2 ECU (target lift setting means, lift control means, rotation speed detection means,
Intake air amount estimation means, determination means and failure determination means)
3 Internal combustion engine 3a Cylinder 4 Intake valve 20 Lift sensor (lift detection means)
21 Crank angle sensor (rotational speed detection means)
22 Air flow sensor (intake air amount detection means)
70 Intake lift variable mechanism 80 Actuator (lift control means)
NE Engine speed QA Intake air volume QES Estimated intake air volume (estimated intake air volume)
QLMT predetermined amount (predetermined value)
SAAIN rotation angle (actual lift)
SACMD target rotation angle (target lift)
SALMT predetermined value

Claims (1)

A variable intake lift mechanism capable of steplessly changing the lift of the intake valve of the internal combustion engine;
Target lift setting means for setting a target lift of the intake valve;
Lift detecting means for detecting the lift of the intake valve as an actual lift;
Lift control means for controlling the intake lift variable mechanism so that the actual lift of the intake valve becomes the target lift;
A rotational speed detection means for detecting the rotational speed of the internal combustion engine;
Intake air amount estimating means for estimating the amount of intake air sucked into the cylinder of the internal combustion engine according to one of the actual lift and target lift of the intake valve and the detected rotational speed;
Intake air amount detection means for detecting the amount of intake air sucked into the cylinder;
A determination means for determining whether or not the actual lift has converged to the target lift by comparing the actual lift and the target lift of the intake valve;
When the determination means determines that the actual lift of the intake valve has converged to the target lift, the deviation between the estimated intake air amount and the detected intake air amount is greater than or equal to a predetermined value Failure determination means for determining that the lift detection means is faulty;
A valve operating apparatus for an internal combustion engine, comprising:

Images