JP2005147115A - Abnormality detection device for valve timing control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress erroneous detection when it is detected that abnormality is generated in a variable valve timing mechanism. <P>SOLUTION: A target valve timing is determined in response to the detected operation state of an internal combustion engine by an operation state detection means for detecting the operation state of the internal combustion engine and the valve timing of at least one of an intake valve or an exhaust valve is changed. Actual valve timing detected by a valve timing detection means is controlled so as to be converged to target valve timing and a target valve displacement angle is retained to a predetermined value at a predetermined vehicle speed for a predetermined time. Difference of the target displacement angle and the actual displacement angle is calculated and if the difference is larger than an abnormality determination value, it is determined that it is abnormal and when the difference is smaller than the abnormality determination value, it is determined that it is normal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an abnormality detection device for a valve timing control device of an internal combustion engine that controls the valve timing of at least one of an intake valve and an exhaust valve of the internal combustion engine in accordance with an operating state.

  Conventionally, a variable valve timing mechanism that changes the valve timing of at least one of an intake valve and an exhaust valve in accordance with the operating state of the engine has been put into practical use. Generally, in order to change the valve overlap amount by changing the opening / closing timing of the intake valve 21, a variable valve timing mechanism (hereinafter referred to as VVT) driven by hydraulic pressure is provided. This VVT is a mechanism for continuously changing the valve timing of the intake valve by changing the rotation phase of the intake camshaft with respect to the rotation of the crankshaft (intake side timing pulley).

  An abnormality detection method in this VVT will be described below. For example, it is shown in Patent Document 1 described below. As shown in FIG. 6 (corresponding to FIG. 9 of Patent Document 1), in the fail determination processing program, in S500, whether or not the duration time counter CVTER is 5 seconds or more and the stop time counter CVTSTP is 5 seconds or more. Is judged. That is, if the absolute value of the difference between the target displacement angle VTT and the calibration actual displacement angle VT is greater than the first predetermined values b and c, it is determined that 5 seconds or more have elapsed, and the change in the calibration actual displacement angle VT is the second predetermined value. It is determined whether it is determined that 5 seconds or more have passed if the value is equal to or less than the value d. If yes, the process proceeds to S510. In S510, it is determined whether or not the current calibration actual displacement angle VT is equal to or greater than 30 ° CA. If it is determined that the calibration actual displacement angle VT is equal to or greater than 30 ° CA, the process proceeds to S520 to advance the advance angle. Fail flag XVTFA. That is, since the calibration actual displacement angle VT is 30 ° CA or more, it is determined that a failure has occurred in the VVT 50 in the advanced state.

  On the other hand, if it is determined in S510 that the current calibration actual displacement angle VT is less than 30 ° CA, 5 sec after the feedback control process for converging the calibration actual displacement angle VT to the target displacement angle VTT is executed. It is determined whether or not the time has passed (S530). If it is determined that 5 seconds have elapsed since the execution of the feedback control process for converging the actual calibration displacement angle VT to the target displacement angle VTT (S530: YES), the retard failure flag XVTFR is set (S540). .

  That is, the calibration actual displacement angle VT is less than 30 ° CA, and the displacement of the calibration actual displacement angle VT is not detected even after 5 seconds have elapsed since the feedback control was executed. It is determined that it has occurred.

JP-A-8-232617 (page 12, FIG. 9)

  However, conventionally, VVT is determined five or more times when the absolute value of the difference between the target displacement angle VTT and the calibration actual displacement angle VT is greater than the first predetermined values b and c, and the change in the calibration actual displacement angle VT is determined. Since it is determined whether or not is less than or equal to the second predetermined value d, it is determined whether the detection is performed at different times depending on the traveling state.

  In order to solve the conventional problems, an object of the present invention is to suppress false detection in detecting whether or not an abnormality has occurred in a variable valve timing mechanism.

The present invention detects an operating state of the internal combustion engine, and an intake valve and an exhaust valve, which are driven at a predetermined timing in synchronization with the rotation of the crankshaft of the internal combustion engine and open and close the intake passage and the exhaust passage leading to the combustion chamber, respectively. An operating state detecting means for performing, a target valve timing determining means for determining a target valve timing according to the operating state of the internal combustion engine detected by the operating state detecting means, and the intake valve or the exhaust valve A variable valve timing mechanism for changing at least one of the valve timings, a valve timing detection means for detecting the actual valve timing of the valve on the side where the variable valve timing mechanism is disposed, and the valve timing detection means The actual valve timing detected by the target Valve timing control means for controlling the variable valve timing mechanism so as to converge to the target valve timing determined by the valve timing determining means, and the target valve timing is held at a first predetermined value for a predetermined time at a predetermined vehicle speed. The target valve timing setting means and the actual valve timing detection means for detecting the actual valve timing,
A difference between the target valve timing and the actual valve timing is calculated, and if the difference is larger than a first predetermined value, it is determined as abnormal, and if the difference is smaller than a second predetermined value, it is determined as normal. .

  The target valve timing described in the claims corresponds to the target displacement angle described in the specification, and the actual valve timing corresponds to the actual displacement angle. The first predetermined value corresponds to an abnormality determination value, and the second predetermined value corresponds to a normal determination value.

  According to the configuration of the present invention, when the vehicle speed reaches a predetermined value, the target valve timing is intentionally displaced greatly to detect VVT abnormality at an early stage.

  As an effect of the above invention, when the vehicle speed reaches a predetermined value, the target valve timing is intentionally displaced greatly to see if the VVT follows, so that the detection condition is satisfied early and the abnormality detection opportunity is advanced. Can do.

A first embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing a basic conceptual configuration of the abnormality detection device of the valve timing control device. In the abnormality detection device of the valve timing control device, a piston is inserted into a cylinder of the internal combustion engine M1, and the piston moves up and down as the crankshaft M2 rotates. A combustion chamber M3 is formed surrounded by the cylinder and the cylinder head, and an intake passage M4 leading to the intake side of the combustion chamber M3 and an exhaust passage M5 leading to the exhaust side are disposed. The intake passage M4 is formed by the intake valve M6 and the exhaust valve M7. And the exhaust passage M5 is opened and closed.

  There is operating state detecting means M8 for detecting the operating state of the internal combustion engine M1, and the detected operating state of the internal combustion engine M1 is input to the target valve timing determining means M9 for determining the target valve timing. A signal from the timing determination means M9 is input to the valve timing control means M12. A signal from the valve timing control means M12 is input to a variable valve timing mechanism M10 that changes the valve timing of at least one of the intake valve M6 and the exhaust valve M7.

  Valve timing detection means M11 for detecting the valve timing of the valve is provided on the side where the variable valve timing mechanism M10 is provided, and the actual valve timing detected by the valve timing detection means M11 is used as the target valve. An input is made to the valve timing control means M12 for controlling the variable valve timing mechanism M10 so as to converge to the target valve timing determined by the timing determination means M9.

  The target valve timing determined by the target valve timing determination means M9 and the actual valve timing detected by the valve timing detection means M11 are input to the abnormality determination means M13 and the normal return determination means M14, respectively.

  A signal from the oil temperature detecting means M15 for detecting the oil temperature of the engine is input to the determination time extending means M17. Further, it is input to the first determination prohibiting means M16. A signal from the determination time extension means M17 is input to the abnormality determination means M13 and the normal return determination means M14.

  A signal from the engine speed detecting means M18 for detecting the engine speed is input to the second determination prohibiting means. Signals from the first determination prohibiting means M16 and the second determination prohibiting means M19 are input to the abnormality determination means M13 and the normal return determination means M14, respectively.

  At this time, the abnormality determination means M13 has an absolute value of a difference between the target valve timing determined by the target valve timing determination means M9 and the actual valve timing detected by the valve timing detection means M11 being not less than a first predetermined value, and When the absolute value of the change amount of the actual valve timing detected by the valve timing detection means M11 is equal to or smaller than the second predetermined value, it is determined that an abnormality has occurred in the variable valve timing mechanism M10.

  Next, the operation will be described. When the internal combustion engine M1 is started, the intake valve M6 and the exhaust valve M7 are driven at a predetermined timing in synchronization with the rotation of the crankshaft M2 of the internal combustion engine M1, and the intake passage M4 and the exhaust passage M5 leading to the combustion chamber M3 are driven. Open and close.

  The variable valve timing mechanism M10 changes the valve timing of at least one of the intake valve M6 and the exhaust valve M7. Further, the operation state detection means M8 detects the operation state of the internal combustion engine M1, and the target valve timing determination means M9 determines a target valve timing according to the operation state of the internal combustion engine M1.

  The valve timing detection means M11 detects the actual valve timing of the valve on the side where the variable valve timing mechanism M10 is provided. Then, the valve timing control means M12 controls the variable valve timing mechanism M10 so that the actual valve timing detected by the valve timing detection means M11 converges to the target valve timing determined by the target valve timing determination means M9.

  At this time, the abnormality determination means M13 has an absolute value of a difference between the target valve timing determined by the target valve timing determination means M9 and the actual valve timing detected by the valve timing detection means M11 being not less than a first predetermined value, and When the absolute value of the change amount of the actual valve timing detected by the valve timing detection means M11 is equal to or smaller than the second predetermined value, it is determined that an abnormality has occurred in the variable valve timing mechanism M10.

  A first embodiment of the present invention will be described with reference to the drawings. First, the configuration of the abnormality detection device VC of the valve timing control device according to the first embodiment will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram showing a gasoline engine system including the abnormality detection device VC of the valve timing control device.

  An engine 10 as an internal combustion engine includes a cylinder block 11 in which a plurality of cylinders are formed, a cylinder head 12 connected to the upper part of the cylinder block 11, and a piston 13 that reciprocates up and down in each cylinder of the cylinder block 11. It has. A crankshaft 14 is connected to the lower end portion of the piston 13, and the crankshaft 14 is rotated when the piston 13 moves up and down.

  Further, a crank angle sensor 40 is disposed in the vicinity of the crankshaft 14, and the crank angle sensor 40 includes a magnetic rotor (not shown) connected to the crankshaft 14 and an electromagnetic pickup (not shown). It consists of. Here, in the electromagnetic pickup, equiangular teeth are formed on the outer periphery of the rotor, and each time the equiangular teeth of the rotor pass in front of the electromagnetic pickup, a pulsed crank angle signal is detected.

  Then, after a reference position signal is generated by a cylinder discrimination sensor 42 described later, the rotation angle (crank angle) of the crankshaft 14 is detected by measuring the number of crank angle signals generated from the crank angle sensor 40.

  Further, the space defined by each cylinder block 11 and the inner wall of the cylinder head 12 and the top of the piston 13 functions as a combustion chamber 15 for burning the air-fuel mixture. A spark plug 16 for igniting the air-fuel mixture is disposed so as to protrude into the combustion chamber 15.

  Each spark plug 16 is connected to the distributor 18 via a plug cord or the like (not shown), and the high voltage output from the igniter 19 is synchronized with the crank angle by the distributor 18. Distributed to. Further, the distributor 18 is provided with an engine speed sensor 41 that is connected to the exhaust camshaft 33 and detects the speed of the crankshaft 14.

  The engine speed sensor 41 includes a magnetic rotor (not shown) that rotates in synchronization with the crankshaft 14 and an electromagnetic pickup (not shown). The rotational speed of the shaft 14 (engine rotational speed NE) is detected. Further, the distributor 18 is provided with a cylinder discrimination sensor 42 for detecting a reference position of the crank at a predetermined ratio from the rotation of the rotor.

  The cylinder block 11 is provided with a water temperature sensor 43 for detecting the temperature (cooling water temperature) THW of the cooling water flowing through the cooling water passage. The cylinder head 12 has an intake port 22 and an exhaust port 32, the intake passage 20 is connected to the intake port 22, and the exhaust passage 30 is connected to the exhaust port 32. An intake valve 21 is disposed in the intake port 22 of the cylinder head 12, and an exhaust valve 31 is disposed in the exhaust port 32.

  An intake side camshaft 23 for opening and closing the intake valve 21 is disposed above the intake valve 21, and an exhaust side camshaft 33 for opening and closing the exhaust valve 31 is disposed above the exhaust valve 31. Is arranged. An intake side timing pulley 27 and an exhaust side timing pulley 34 are attached to one end of each camshaft 23, 33, and each timing pulley 27, 34 is connected to the crankshaft 14 via a timing belt 35. Has been.

  Therefore, when the engine 10 is operated, the rotational driving force is transmitted from the crankshaft 14 to the camshafts 23 and 33 via the timing belt 35 and the timing pulleys 27 and 34, and the camshafts 23 and 33 rotate, thereby The valve 21 and the exhaust valve 31 are driven to open and close. These valves 21 and 31 are synchronized with the rotation of the crankshaft 14 and the vertical movement of the piston 13, that is, in a series of four strokes in the engine 10 including an intake stroke, a compression stroke, an explosion / expansion stroke, and an exhaust stroke. Synchronously, it is driven at a predetermined opening / closing timing.

  Further, a cam angle sensor 44 for detecting the valve timing of the intake valve 21 is disposed in the vicinity of the intake side cam shaft 23, and this cam angle sensor 44 is connected to the intake side cam shaft 23. It is composed of a magnetic rotor (not shown) and an electromagnetic pickup (not shown). A plurality of teeth are formed at equal angles on the outer periphery of the magnetic rotor. For example, before the compression TDC of a predetermined cylinder, the intake camshaft 23 rotates between BTDC 90 ° and 30 °. The accompanying pulse cam angle signal is detected.

  An air cleaner 24 is connected to the air intake side of the intake passage 20, and a throttle valve 26 that is opened and closed in conjunction with an accelerator pedal (not shown) is disposed in the intake passage 20. The intake air amount is adjusted by opening and closing the accelerator pedal.

  In the vicinity of the throttle valve 26, a throttle sensor 45 for detecting the throttle opening degree TA is provided. Further, a surge tank 25 for suppressing intake pulsation is formed on the downstream side of the throttle valve 26. The surge tank 25 is provided with an intake pressure sensor 46 that detects the intake pressure in the surge tank 25. In addition, an injector 17 for supplying fuel to the combustion chamber 15 is disposed near the intake port 22 of each cylinder. Each injector 17 is an electromagnetic valve that is opened by energization, and fuel that is pumped from a fuel pump (not shown) is supplied to each injector 17.

  Therefore, when the engine 10 is in operation, the air filtered by the air cleaner 24 is taken into the intake passage 20 and fuel is injected from each injector 17 toward the intake port 22 simultaneously with the intake of the air. As a result, an air-fuel mixture is generated at the intake port 22, and the air-fuel mixture is sucked into the combustion chamber 15 as the intake valve 21 is opened in the intake stroke.

  A catalytic converter 36 having a built-in three-way catalyst for purifying exhaust gas is disposed in the middle of the exhaust passage 30. An oxygen sensor 47 that detects the oxygen concentration in the exhaust gas is disposed in the exhaust passage 30.

  In the gasoline engine system in the present embodiment, a variable valve timing mechanism 50 (hereinafter referred to as “VVT”) driven by hydraulic pressure is arranged in order to change the valve overlap amount by changing the opening / closing timing of the intake valve 21. Established. The VVT 50 is a mechanism for continuously changing the valve timing of the intake valve 21 by changing the rotation phase of the intake side camshaft 23 with respect to the rotation of the crankshaft 14 (intake side timing pulley 27).

  Next, the system configuration of the VVT 50 will be described with reference to FIG. FIG. 3 is an explanatory view showing a cross section in the vicinity of the intake camshaft 23 where the VVT 50 is disposed, and the entire control system of the VVT 50.

  The control system of the VVT 50 includes various sensors such as the VVT 50, an oil control valve 80 (hereinafter referred to as “OCV”) that applies a driving force to the VVT 50, a cam angle sensor 44 that detects a cam angle signal, and a cam angle sensor 44. ECU 70 for driving and controlling the OCV 80 based on the input signal.

  The VVT 50 is disposed between the intake side camshaft 23 and the intake side timing pulley 27, and the intake side camshaft 23 is rotatably supported between the cylinder head 12 and the bearing cap 51. An intake side timing pulley 27 is mounted in the vicinity of the front end of the intake side camshaft 23 so as to be relatively rotatable, and an inner cap 52 is provided with a hollow bolt 53 and a pin 54 at the front end of the intake side camshaft 23. Is attached so as to be integrally rotatable.

  A housing 56 having a cap 55 is attached to the intake side timing pulley 27 by a bolt 57 and a pin 58 so as to be integrally rotatable. The housing 56 allows the tip of the intake side camshaft 23 and the inner cap 52 to be rotated. The whole is covered. In addition, a large number of external teeth 27 a for hooking the timing belt 35 are formed on the outer periphery of the intake side timing pulley 27.

  The intake side camshaft 23 and the intake side timing pulley 27 are connected by a ring gear 59 interposed between the housing 56 and the inner cap 52. The ring gear 59 has a substantially annular shape, and is housed in a space S surrounded by the intake side timing pulley 27, the housing 56, and the inner cap 52 so as to reciprocate in the axial direction of the intake side camshaft 23. . A large number of teeth 59 a and 59 b are formed on the inner and outer periphery of the ring gear 59.

  Correspondingly, a large number of teeth 52 a and 56 b are formed on the outer periphery of the inner cap 52 and the inner periphery of the housing 56. All of these teeth 59a, 59b, 52a, 56b are helical teeth whose tooth lines intersect with the axis of the intake camshaft 23 at a predetermined angle. That is, a helical spline is formed in which the teeth 52a and the teeth 59a mesh with each other, and the teeth 56b and the teeth 59b mesh with each other.

  The rotation of the intake side timing pulley 27 is transmitted to the intake side camshaft 23 through the housing 56 and the inner cap 52 by these meshing. Since each tooth 59a, 59b, 52a, 56b is a helical tooth, when the ring gear 59 moves in the axial direction of the intake side camshaft 23, a twisting force is applied to the inner cap 52 and the housing 56, and the intake side The camshaft 23 moves relative to the intake side timing pulley 27.

  In the space S, in order to move the ring gear 59 in the axial direction, a first hydraulic chamber 60 is provided on the distal end side of the ring gear 59, and a second hydraulic chamber 61 is provided on the proximal end side of the ring gear 59. The bearing cap 51 has a first hydraulic pressure supply hole 51a and a second hydraulic pressure supply hole 51b. Further, in the intake side camshaft 23, the first hydraulic pressure supply passage 62 that communicates the first hydraulic pressure supply hole 51a and the first hydraulic chamber 60, and the second hydraulic pressure supply hole 51b and the second hydraulic chamber 61 communicate with each other. The second hydraulic pressure supply path 63 is formed.

  Then, the lubricating oil sucked up from the oil pan 65 by the hydraulic pump 64 is supplied to the hydraulic supply holes 51a and 51b through the oil filter 66 with a predetermined pressure. In addition, an OCV 80 is connected to each of the hydraulic supply holes 51a and 51b in order to selectively supply the hydraulic pressure to the respective hydraulic chambers 60 and 61 via the respective hydraulic supply paths 60 and 61.

  The OCV 80 is a 4-port directional control valve that switches the flow direction of the lubricating oil by a plunger 83 driven by an electromagnetic actuator 81 and a coil spring 82 reciprocating the spool 84 in the axial direction. The opening degree of the electromagnetic actuator 81 is adjusted by duty control, and the hydraulic pressure supplied to the hydraulic chambers 60 and 61 is adjusted.

  The casing 85 of the OCV 80 has a tank port 85t, an A port 85a, a B port 85b, and a reservoir port 85r. The tank port 85t is connected to the oil pan 65 via the hydraulic pump 64, the A port 85a is connected to the first hydraulic pressure supply hole 51a, and the B port 85b is connected to the second hydraulic pressure supply hole 51b. Yes. The reservoir port 85r is in communication with the oil pan 65.

  The spool 84 is a cylindrical valve body. The four lands 84a seal the flow of the lubricating oil between the two ports, and the passages 84b, 2b that communicate between the two ports and allow the flow of the lubricating oil. Two passages 84c.

  In the VVT 50 having such a configuration, when the OCV 80 is driven and controlled, and the spool 84 is moved to the left in the drawing, the passage 84b communicates the tank port 85t and the A port 85a to the first hydraulic pressure supply hole 51a. Lubricating oil is supplied. The lubricating oil supplied to the first hydraulic pressure supply hole 51 a is supplied to the first hydraulic chamber 60 via the first hydraulic pressure supply path 62, and the hydraulic pressure is applied to the tip side of the ring gear 59.

  At the same time, the passage 84c communicates the B port 85b and the reservoir port 85r, and the lubricating oil in the second hydraulic chamber 61 is supplied to the second hydraulic pressure supply path 63, the second hydraulic pressure supply hole 51b, and the OCV 80 B port. The oil pan 65 is discharged through the reservoir port 85r.

  Accordingly, the ring gear 59 is moved while being rotated to the base end side (right side in the drawing) by the hydraulic pressure applied to the front end side, and the intake side camshaft 23 is twisted via the inner cap 52. As a result, the rotation phase of the intake side camshaft 23 with respect to the intake side timing pulley 27 (crankshaft 14) is changed, the intake side camshaft 23 rotates from the most retarded position to the most advanced position, and the intake valve 21 The valve opening timing is advanced.

  The intake valve 21 whose valve opening timing has been advanced in this way is opened while the exhaust valve 31 is open, and there is a valve overlap period in which the intake valve 21 and the exhaust valve 31 are simultaneously opened. Enlarged. The movement of the ring gear 59 toward the proximal end side is restricted by the ring gear 59 coming into contact with the intake side timing pulley 27, and when the ring gear 59 comes into contact with the intake side timing pulley 27 and stops, the intake valve 21 is moved. The valve opening timing is the earliest.

  On the other hand, when the OCV 80 is driven and the spool 84 is moved to the right in the drawing, the passage 84b communicates the tank port 85t and the B port 85b, and the lubricating oil is supplied to the second hydraulic pressure supply hole 51b. . The lubricating oil supplied to the second hydraulic pressure supply hole 51 b is supplied to the second hydraulic chamber 61 via the second hydraulic pressure supply path 63, and the hydraulic pressure is applied to the base end side of the ring gear 59.

  At the same time, the passage 84c communicates the A port 85a and the reservoir port 85r, and the lubricating oil in the first hydraulic chamber 60 passes through the first hydraulic supply path 62, the first hydraulic supply hole 51a, and the OCV 80 A port. The oil pan 65 is discharged through the reservoir port 85r.

  Therefore, the ring gear 59 is moved while rotating to the distal end side (left side in the drawing) by the hydraulic pressure applied to the proximal end side, and a reverse twist is applied to the intake side camshaft 23 via the inner cap 52. . As a result, the rotation phase of the intake side camshaft 23 with respect to the intake side timing pulley 27 (crankshaft 14) is changed, the intake side camshaft 23 rotates from the most advanced position to the most retarded position, and the intake valve 21 The valve opening timing is delayed.

  Thus, by delaying the valve opening timing of the intake valve 21, the valve overlap period during which the intake valve 21 and the exhaust valve 31 are simultaneously opened is reduced or eliminated. The movement of the ring gear 59 toward the tip side is restricted by the ring gear 59 coming into contact with the housing 56, and when the ring gear 59 comes into contact with the housing 56 and stops, the opening timing of the intake valve 21 becomes the latest. .

  The valve timing of the intake valve 21 changed by the VVT 50 is calculated by the cam angle signal output from the cam angle sensor 44 and the crank angle signal output from the crank angle sensor 40.

  That is, for example, the time required from the input of the cam angle signal to the ECU 70 until the input of the BTDC 30 ° crank angle signal (reference timing signal) is measured using the engine speed NE, and the time is known. The actual valve displacement angle VTB of the intake camshaft 23 with respect to the crankshaft 14 is calculated by converting the valve displacement angle into the valve displacement angle using the relationship between the time and the crank angle.

  Next, the control system of the abnormality detection device VC of the valve timing control device according to this embodiment will be described with reference to the control block diagram shown in FIG. The control system of the abnormality detection device VC of the valve timing control device according to the present embodiment is configured with an electronic control unit 70 (hereinafter referred to as “ECU”) as a core. The ECU 70 implements target valve timing determination means, valve timing control means, abnormality determination means, normal return determination means, first and second determination prohibition means, determination time extension means, and the like.

  The ECU 70 has a ROM 71 that stores an abnormality determination and normal recovery determination processing program for determining abnormality and normal recovery in the VVT 50 executed as a main routine, and a map for changing valve timing corresponding to various conditions. . The ECU 70 also has various control programs such as a fail determination processing program, a normal return determination processing program, and a start condition determination processing program that are executed as a subroutine.

  Further, the ECU 70 executes calculation processing based on a control program stored in the ROM 71, a RAM 73 that temporarily stores calculation results in the CPU 72, data input from each sensor, and the like in the RAM 73 when power supply is stopped. A backup RAM 74 for holding various stored data is provided.

  The CPU 72, ROM 71, RAM 73, and backup RAM 74 are connected to each other via a bidirectional bus 75, and are connected to an input interface 76 and an output interface 77.

  A crank angle sensor 40, an engine speed sensor 41, a cylinder discrimination sensor 42, a water temperature sensor 43, a cam angle sensor 44, a throttle sensor 45, an intake pressure sensor 46, an oxygen sensor 47, and the like are connected to the input interface 76. If the signal output from each sensor is an analog signal, it is converted to a digital signal by an A / D converter (not shown) and then output to the bidirectional bus 75.

  The output interface 77 is connected to external circuits such as the injector 17, the igniter 19, and the OCV 80, and these external circuits are controlled based on the calculation result of the control program executed by the CPU 72.

  Next, an abnormality determination and normal return determination program in the abnormality detection device VC of the valve timing control device according to the first embodiment having the above-described configuration will be described with reference to the flowchart shown in FIG.

  The abnormality determination and normal return determination program in the subroutine shown in FIG. 1 will be described below. When the main routine starts, a start condition determination processing program is executed in a subroutine. In step 100, it is determined whether or not the engine has been warmed up.

  It is determined whether the engine water temperature ethw> = 75 ° C., that is, whether the engine has been warmed up. In addition, the engine water temperature used as a judgment value is not limited to 75 degreeC, This value is determined by a test. If negative (NO) here, that is, if the warm-up is not completed, the process returns to the original routine. If it is affirmative (YES) in step 100, the process proceeds to step 110. In step 110, it is determined whether or not the vehicle speed is a predetermined value A (for example, 20 km / h). If no, return to the original routine. If the determination is affirmative, the routine proceeds to step 120 corresponding to the target valve timing setting means, and the target displacement angle is changed to be larger than the displacement displacement angle immediately before the predetermined time B (for example, 1 second). The displacement angle amount is set larger than the size given in the map.

  Subsequently, the process proceeds to step 130 corresponding to the actual valve timing detection means, and the target displacement angle is compared with the actual displacement angle to obtain the absolute value of the difference. Subsequently, the routine proceeds to step 140, where it is determined whether or not the difference is larger than an abnormality determination value (for example, 10 °). If the result is affirmative, the routine proceeds to step 150, where it is confirmed whether or not the duration of the abnormality difference has exceeded the determination value. Subsequently, the routine proceeds to step 160, where the VVT abnormality flag is turned ON. On the program, wxdvt = ON. Proceeding to step 170, it is determined that there is an abnormality and a warning is given.

  If NO in step 140, the process proceeds to step 180, and it is determined whether or not the difference is less than a normal determination value. If the result is affirmative, the routine proceeds to step 190, and if the normal difference continuation time is not less than the determination value, the VVT normal flag is turned ON. On the program, wxdvt = ON. Proceed to step 210 and processed as normal. As a result, when the vehicle speed reaches a predetermined value, the target displacement angle is intentionally displaced greatly to see if the VVT follows, so that the detection condition is established early, so that the abnormality detection can be accelerated.

6 is a flowchart of a VVT abnormality determination processing program executed as a subroutine of the first embodiment. 1 is a schematic configuration diagram of a gasoline engine system of Example 1. FIG. 1 is a schematic configuration diagram of a variable valve timing mechanism of Embodiment 1. FIG. It is a control block diagram concerning the abnormality detection of the valve timing control apparatus of Example 1. It is a control block diagram in the abnormality detection apparatus of the conventional valve timing control apparatus. It is a flowchart of the fail determination processing program executed as a conventional subroutine.

Explanation of symbols

M8: Operating state detection means M9: Target valve timing determination means M10: Variable valve timing mechanism M11: Valve timing detection means M12: Valve timing control means 120: Target valve timing setting means 130: Actual valve timing detection means

Claims (1)

An intake valve and an exhaust valve, which are driven at a predetermined timing in synchronization with the rotation of the crankshaft of the internal combustion engine and open and close the intake passage and the exhaust passage respectively leading to the combustion chamber, and an operation for detecting the operating state of the internal combustion engine At least one of state detection means, target valve timing determination means for determining target valve timing according to the operating state of the internal combustion engine detected by the operating state detection means, and the intake valve or the exhaust valve A variable valve timing mechanism for changing the valve timing, a valve timing detection means for detecting the actual valve timing of the valve on the side where the variable valve timing mechanism is disposed, and the valve timing detection means The actual valve timing is A valve timing control means for controlling the variable valve timing mechanism so as to converge to the target valve timing determined by the driving determination means, and a target for holding the target valve timing at a first predetermined value for a predetermined time at a predetermined vehicle speed. The valve timing setting means and the actual valve timing detection means for detecting the actual valve timing,
A difference between the target valve timing and the actual valve timing is calculated, and if the difference is larger than a first predetermined value, it is determined as abnormal, and if the difference is smaller than a second predetermined value, it is determined as normal. An abnormality detection device for a valve timing control device.

Images