JP2008298015A - Variable valve gear control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable minimum operation in abnormal communication of a communication means 30 in a variable valve gear control device. <P>SOLUTION: ECM10 computes a target value of a valve working angle (VEL) of an intake valve and transmits to VEL-C/U20. The VEL-C/U20 controls the VEL according to the VEL target value from the ECM10, detects a VEL actual value, and transmits to the ECM10. Here, the ECM10 is provided with a function of fixing the VEL actual value to a predetermined specific value equivalent to a medium load in detecting abnormal communication. The VEL-C/U20 is provided with a function of fixing the VEL target value to the value same to the predetermined specific value in detecting abnormal communication. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable valve control apparatus for an internal combustion engine, and more particularly to an apparatus that uses two control units and communicates between the control units.

  In the variable valve control apparatus for an internal combustion engine described in Patent Document 1, in addition to controlling the valve timing of the intake valve, the valve operating angle and the lift amount are controlled.

In addition, the target value of the valve operating angle (lift amount) of the intake valve is calculated and the valve operating angle (lift amount) is controlled based on this target value, while the actual value of the valve operating angle (lift amount) is detected. Based on this, the limit value on the advance side of the valve timing of the intake valve is set, and the valve timing is controlled so as not to exceed the limit value on the advance side, thereby preventing interference between the intake valve and the piston. .
JP 2002-285871 A

  By the way, in the variable valve control apparatus for an internal combustion engine, the first and second control units are used, the first control unit calculates the target value of the valve operating angle of the intake valve, and transmits it to the second control unit. When the second control unit controls the valve operating angle of the intake valve according to the target value from the first control unit and detects the actual value of the valve operating angle and transmits it to the first control unit, the following is performed. There are some problems.

  When the communication means between the first and second control units has a communication error due to noise or the like, or a communication driver (microcomputer communication function) or harness / connector failure, the target value of the valve operating angle is calculated. The first control unit cannot recognize the actual value, and the second control unit that controls the valve operating angle cannot recognize the target value and becomes uncontrollable.

  The present invention has been made in view of such a situation, and an object of the present invention is to ensure minimum control even when a communication abnormality occurs.

  Therefore, in the present invention, the actual value of the valve operating angle received from the second control unit when the communication abnormality is detected is detected by the first control unit that calculates the target value of the valve operating angle. The second predetermined control unit is provided with a fail safe means for fixing the predetermined value to the predetermined value, and the second control unit for controlling the valve operating angle has a predetermined target value for the valve operating angle received from the first control unit when a communication abnormality is detected. It is set as the structure which comprises the fail safe means fixed to the same value.

  According to the present invention, even if a communication abnormality occurs, the actual value of the valve operating angle recognized by the first control unit and the target value of the valve operating angle recognized by the second control unit are set to the same value and recognized. The minimum driving (running) can be achieved by eliminating the deviation and setting the fixed value to a predetermined value corresponding to a predetermined medium load.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a system diagram of an engine (direct injection spark ignition type internal combustion engine) showing an embodiment of the present invention.

  An electric throttle valve 3 is installed in the intake passage 2 of the engine 1. The opening degree of the electrically controlled throttle valve 3 is controlled by an engine control unit (hereinafter referred to as ECM) 10. Air that is controlled by the electric throttle valve 3 is taken into the combustion chamber 5 of the engine 1 through the intake valve 4.

  The intake valve 4 has a variable valve operating device (valve operating angle and lift amount variable device) that can continuously change the valve operating angle (open period) of the intake valve 4, more specifically, the valve operating angle and the lift amount. VEL device; VEL actuator 49) and a valve timing variable device (VTC device; VTC actuator 51) capable of continuously changing the valve timing (center phase of the valve operating angle) of the intake valve 4 are provided. . Details will be described later.

  A fuel injection valve 7 is installed in the combustion chamber 5 of the engine 1 together with a spark plug 6. The fuel injection valve 7 is energized to the solenoid by an injection pulse signal output in the intake stroke or compression stroke in synchronization with the engine rotation from the ECM 10 to open the valve, and the fuel adjusted to a predetermined pressure in the combustion chamber 5 Is supposed to be injected.

  The fuel injected into the combustion chamber 5 forms an air-fuel mixture, and is ignited and burned by the spark plug 6 at the ignition timing determined by the ECM 10. The exhaust gas after combustion is discharged to the exhaust passage 9 via the exhaust valve 8.

  The ECM 10 receives, as engine operating conditions, an accelerator opening APO detected by the accelerator pedal sensor 11, an engine speed Ne detected by the crank angle sensor 12, an intake air amount Qa detected by the air flow meter 13, and the like. ing.

  Next, the variable valve operating device of the intake valve 4 will be described with reference to FIG.

  Above the valve lifter 40 at the end of the intake valve 4 (two are provided for each cylinder), a camshaft 41 that is driven to rotate around the shaft in conjunction with a crankshaft (not shown) extends in the cylinder row direction. ing. A swing cam 42 is swingably mounted on the outer periphery of the cam shaft 41 corresponding to the intake valve 4. The swing cam 42 abuts against and presses the valve lifter 40, thereby The valve 4 is driven to open and close against the spring force of a valve spring (not shown).

  Here, between the cam shaft 41 and the swing cam 42, the posture of the link that mechanically links both 41 and 42 is changed, and the valve operating angle (open period) and the lift amount of the intake valve 4 are continuously set. A valve operating angle and lift amount variable device (VEL device) that can be variably controlled is provided.

  The VEL device includes a drive cam 43 that is eccentrically provided on the cam shaft 41 and rotates integrally with the cam shaft 41, a ring-shaped link 44 that is fitted on the outer periphery of the drive cam 43 so as to be relatively rotatable, and a cam shaft 41. A control shaft 45 extending substantially parallel to the cylinder row direction, a control cam 46 provided eccentrically with respect to the control shaft 45 and rotating integrally with the control shaft 45, and rotatable relative to the outer periphery of the control cam 46 And a rocker arm 47 whose one end is rotatably connected to the tip of the ring-shaped link 44, and is rotatably connected to the other end of the rocker arm 47 and the tip of the swing cam 42. 42 has a rod-like link 48 that mechanically cooperates.

  The cam shaft 41 and the control shaft 45 are rotatably supported on the cylinder head side of the engine via a bearing bracket. One end of the control shaft 45 is connected to an output end of an actuator (VEL actuator) 49 for changing the valve operating angle and lift amount. The VEL actuator 49 causes the control shaft 45 to move around the axis within a predetermined control angle range. While being rotated, it is held at a predetermined rotational phase.

  With such a configuration, when the cam shaft 41 rotates in conjunction with the crankshaft, the ring-shaped link 44 substantially translates via the drive cam 43, and the rocker arm 47 swings around the control cam 46, The swing cam 42 swings through the rod-shaped link 48, and the intake valve 4 is driven to open and close.

  Further, when the control shaft 45 is rotated by the VEL actuator 49, the center position of the control cam 46, which is the rocking center of the rocker arm 47, is changed, and the postures of the links 44, 48, etc. are changed. The swing angle range of 42 changes. As a result, the valve operating angle and the lift amount continuously change while the central phase of the valve operating angle remains substantially constant. More specifically, the valve operating angle and the lift amount are increased by rotating the control shaft 45 in one direction, and the valve operating angle and the lift amount are decreased by rotating in the other direction. Yes. If the valve operating angle is determined, the valve lift amount is uniquely determined.

  Therefore, by duty-controlling the energization amount of the VEL actuator 49, the rotational phase of the control shaft 45 can be changed to change the valve operating angle and the lift amount of the intake valve 4 (see A in FIG. 3). Thus, a valve operating angle and lift amount variable device (VEL device) is configured.

  On the other hand, the camshaft 41 is driven by the rotation of the crankshaft being input to the sprocket 50 by the timing belt, but the rotational phase of the camshaft 41 can be controlled between the sprocket 50 and the camshaft 41 to change the valve timing. A rotary actuator (VTC actuator) 51 is mounted.

  Therefore, by duty-controlling the energization amount of the VTC actuator 51, the rotational phase between the crankshaft and the camshaft 41 can be changed, and the valve timing (center phase of the valve operating angle) of the intake valve 4 can be changed. (Refer to A in FIG. 3) This forms a variable valve timing device (VTC device).

  Here, as shown in FIG. 4, the VTC actuator 51 of the VTC device is controlled by the ECM 10 that is the first control unit, while the VEL actuator 49 of the VEL device is the ECM 10 that is the first control unit. Control is performed by a second control unit (hereinafter referred to as VEL-C / U) 20, which is different from the above.

  For each control, the ECM 10 is provided with a function of detecting a VTC actual value (actual valve timing) by inputting a signal of the VTC position sensor 51S that detects the actual position of the VTC actuator 51, and VEL-C. / U20 has a function of detecting a VEL actual value (actual valve operating angle) by inputting a signal of a VEL position sensor 49S that detects the actual position of the VEL actuator 49.

  However, the function for calculating the VEL target value (target valve operating angle) according to the engine operating condition and the function for calculating the VTC target value (target valve timing) according to the engine operating condition include various sensors relating to the engine operating condition. Are concentrated on the ECM 10 to which the signals are input.

  For this reason, the ECM 10 and the VEL-C / U 20 are connected by a communication means (CAN) 30 so that the VEL target value (target valve operating angle) is transmitted from the ECM 10 to the VEL-C / U 20. The CAN (Controller Area Network) enables data transmission / reception between control units by connecting each control unit with two communication lines and performing serial communication.

Further, the VEL actual value (actual valve operating angle) is transmitted from the VEL-C / U 20 to the ECM 10. This is because the actual valve operating angle is used for the calculation of the intake air amount in the ECM 10 and is related to the valve timing control for the following reasons. The control range is set so that the engine performance (operation performance, exhaust purification performance, etc.) can be maximized by each control characteristic. However, when these controls are used in combination, for example, as shown in FIG. 3B, the valve timing is controlled to the advance side and the valve operating angle is controlled to the wide angle side (the valve lift amount is the high lift side). The valve lift amount at the top dead center of the piston becomes extremely large, and there is a possibility that interference occurs between the intake valve and the piston.

  In order to limit the maximum advance angle value of the VTC device of the intake valve and the maximum operating angle (maximum lift amount) of the VEL device so that the valve lift amount is not excessively increased near the top dead center of the piston, mechanically by a stopper or the like. By limiting, the control range is narrowed, and the upper limit of the control amount is also limited at the valve timing and valve operating angle (valve lift amount) at which no interference occurs between the intake valve and the piston. The combined use of the valve timing control and the valve operating angle control of the valve cannot provide sufficient effects of increasing output and improving exhaust performance.

  Therefore, assuming that the response of the VEL device is higher than that of the VTC device of the intake valve, the advance side of the VTC target value (target valve timing) according to the actual value of VEL (actual valve operating angle) A limit value is set, and when the VTC target value is calculated, it is limited so that it does not exceed the advance side limit value.

  For this reason, the VEL actual value is transmitted from the VEL-C / U 20 having the function of detecting the VEL actual value to the ECM 10 having the function of calculating the VTC target value.

  FIG. 5 is a flowchart of main control on the ECM 10 side, which will be described.

  The first steps S111 and S112 are steps for determining the fail safe flags fECFMFS2 and fECMFS1 described later. Since fECFMFS2 = 0 and fECFMFS1 = 0 in the normal state, the process proceeds to S11.

  In S11, the VEL target value (target valve operating angle) is obtained by referring to the map based on the engine speed Ne and the basic fuel injection amount Tp (= K × Qa / Ne; K is a constant) representing the engine load. ) Is calculated. The calculated VEL target value is transmitted to VEL-C / U by communication means.

  In S12, the VEL actual value (actual valve operating angle) received by the communication means from VEL-C / U, which is a value detected by VEL-C / U via the VEL position sensor, is read.

  In S13, the VTC target value (target valve timing) is calculated by referring to the map based on the engine speed Ne and the basic fuel injection amount Tp representing the engine load.

  In S14, the limit value (advance side limit value) of the VTC target value (target valve timing) is calculated by referring to the table based on the VEL actual value (actual valve operating angle).

  The limit value of the VTC target value (target valve timing) is the range where the VEL actual value (actual valve operating angle) is small to medium, and the intake valve and piston interfere even if the VTC is controlled to the most advanced angle value. Therefore, the position is the same as the most advanced position regulated by the stopper mechanism of the VTC.

  On the other hand, when the valve operating angle of the intake valve becomes a large region, the VTC may approach the piston at the top dead center as the VTC approaches the most advanced angle position. The angle is gradually set to the retard side.

  In S15, the VTC target value obtained in S13 is compared with the limit value obtained in S14. If VTC target value> limit value (when the VTC target value is on the advance side of the limit value), the process proceeds to S16. Then, after limiting the VTC target value as VTC target value = limit value, the process proceeds to S17. When VTC target value ≦ limit value (when the VTC target value is retarded from the limit value), the process directly proceeds to S17.

  In S17, the VTC actual value (actual valve timing) is detected based on the detection signal of the VTC position sensor.

  In S18, a deviation VTCERR between the VTC target value (target valve timing) and the VTC actual value (actual valve timing) is calculated.

  In S19, in accordance with the deviation VTCERR, a control output for the VTC actuator is calculated and output so as to make the VTC actual value coincide with the VTC target value, feedback control is performed, and the valve timing is controlled.

  Specifically, first, based on the deviation VTCERR and the feedback gains Gp (proportional component), Gi (integral component), Gd (derivative component), the proportional component control amount VTCp and the integral component control amount are expressed by the following equations. VTCi and differential control amount VTCd are obtained respectively.

VTCp = Gp · VTCERR
VTCi = VTCiz + Gi · VTCERR
VTCd = Gd · (VTCERR−VTCERRz)
The subscript z indicates the previous value.

  Next, the basic duty value BASDTYvtc and the control amounts VTCp, VTCi, and VTCd are added to calculate a VTC duty value VTCDTY (see the following equation), and this is used as an output signal to drive the VTC actuator.

VTCDTY = BASDTYvtc + VTCp + VTCi + VTCd
Here, when the VTC duty value VTCDTY = basic duty value BASDTYvtc (for example, 50%), the VTC actuator is fixed at the position at that time, and is driven by being set to the plus side or the minus side for the deviation. If the deviation disappears, VTC duty value VTCDTY = basic duty value BASDTYvtc, which is fixed at that position. The same applies to the VEL actuator.

  FIG. 6 is a flowchart of main control on the VEL-C / U 20 side, which will be described.

  The first steps S211 and S212 are steps for determining the fail safe flags fVELFS2 and fVELFS1 described later. Since fVELFS2 = 0 and fVELFS1 = 0 in the normal state, the process proceeds to S21.

  In S21, the VEL target value (target valve operating angle) that is a value calculated by the ECM and received from the ECM by the communication means is read.

  In S22, the VEL actual value (actual valve operating angle) is detected based on the detection signal of the VEL position sensor. The detected VEL actual value is transmitted to the ECM by the communication means.

  In S23, a deviation VELERR between the VEL target value (target valve operating angle) and the VEL actual value (actual valve operating angle) is calculated.

  In S24, in accordance with the deviation VELERR, a control output for the VEL actuator is calculated and output so that the actual VEL value matches the VEL target value, feedback control is performed, and the valve operating angle is controlled. The details of the feedback control are the same as the feedback control for the VTC actuator in the ECM.

  By the way, in the above system, when the communication means 30 between the ECM 10 and the VEL-C / U 20 causes a communication abnormality due to noise or the like, or a communication driver (microcomputer communication function) or a harness / connector failure. Since the VEL target value and VEL actual value sent by the communication means 30 become abnormal, VTC control (valve timing control) including VTC limit value setting based on the VEL actual value in the ECM 10 and VEL in the VEL-C / U 20 This impedes VEL control (valve operating angle control) based on the target value.

  Accordingly, a communication abnormality of the communication unit 30 is detected, and a fail safe process is performed when the communication abnormality is detected.

  An outline of detection of communication abnormality will be described.

  The communication abnormality detecting means provided in each control unit (ECM10, VEL-C / U20) monitors the value of the message counter transmitted while counting up from the other control unit via the communication means at a predetermined cycle. Thus, a communication abnormality is detected.

  Specifically, as shown in FIG. 9, the ECM 10 transmits the message counter ECMVELCK to the VEL-C / U 20 while counting up at a predetermined cycle, and the VEL-C / U 20 sets the value of the message counter ECMVELCK. Monitor and consider abnormal when not counting up in a given cycle.

  The VEL-C / U 20 transmits a message counter VELECKCK to the ECM 10 while counting up at a predetermined cycle. The ECM 10 monitors the value of the message counter VELECKCK and does not count up at a predetermined cycle. Considered abnormal.

  FIG. 7 is a flowchart of communication abnormality detection (executed every unit time) in the ECM 10, which will be described.

  In S101, for the message counter VELECKCK from VEL-C / U, a difference (counter deviation) from the previous value VELECKCKz is obtained to determine whether it is other than 1. In the case of NO (in the case of = 1), since it is normal, the process proceeds to S102 and the increment counter VELECMNG = 0 is set.

  On the other hand, in the case of YES (in the case of ≠ 1), since the count is not correctly counted up and it is abnormal, the process proceeds to S103, and the increment counter VELECMNG is incremented by 1 (VELECMNG = VELCMNNGz + 1).

  In next step S104, it is determined whether or not the increment counter VELECMNG is equal to or greater than a predetermined first threshold value CNG1 (VELECMNG ≧ CNG1). In the case of NO (when VELECMNG <CNG1), it is regarded as normal and the process proceeds to S105, and the first failsafe flag fECFMS1 = 0 is set. Furthermore, it progresses to S108 and makes 2nd fail safe flag fECFMS2 = 0.

  On the other hand, if the determination in S104 is YES (when VELECMNG ≧ CNG1), it is determined that the communication is abnormal, and the process proceeds to S106 to set the first failsafe flag fECFMS1 = 1. Thereafter, the process proceeds to S107.

  In S107, it is determined whether or not the increment counter VELECMNG is greater than or equal to a predetermined second threshold value CNG2 (VELECMNG ≧ CNG2; naturally CNG2> CNG1). In the case of NO (VELECMNG <CNG2), the process proceeds to S108, and the second failsafe flag fECFMS2 = 0 is set.

  On the other hand, if the determination in S107 is YES (VELECMNG ≧ CNG2), it is determined that the failure is not a short-term abnormality such as noise, and the process proceeds to S109, where the second failsafe flag fECFMFS2 = 1. To do.

  FIG. 8 is a flowchart of communication abnormality detection (executed every unit time) in the VEL-C / U 20, which will be described.

  In S201, a difference (counter deviation) from the previous value ECMVELCKz is determined for the message counter ECMVELCK from the ECM to determine whether it is other than 1. In the case of NO (in the case of = 1), since it is normal, the process proceeds to S202, and the increment counter ECMVELNG = 0 is set.

  On the other hand, in the case of YES (in the case of ≠ 1), since the count is not correctly incremented and is abnormal, the process proceeds to S203, and the increment counter ECMVELNG is incremented by 1 (ECMVELNG = ECMVELNGz + 1).

  In next step S204, it is determined whether or not the increment counter ECMVELNG is equal to or greater than a predetermined first threshold value CNG1 (ECMVELNG ≧ CNG1). In the case of NO (when ECMVELNG <CNG1), it is regarded as normal and the process proceeds to S205 to set the first failsafe flag fVELFS1 = 0. Furthermore, it progresses to S208 and sets the 2nd fail safe flag fVELFS2 = 0.

  On the other hand, if the determination in S204 is YES (ECMVELNG ≧ CNG1), it is determined that the communication is abnormal, the process proceeds to S206, and the first failsafe flag fVELFS1 = 1 is set. Thereafter, the process proceeds to S207.

  In S207, it is determined whether or not the increment counter ECMVELNG is greater than or equal to a predetermined second threshold value CNG2 (ECMVELNG ≧ CNG2; naturally CNG2> CNG1). In the case of NO (when ECMVELNG <CNG2), the process proceeds to S208, and the second fail-safe flag fVELFS2 = 0 is set.

  On the other hand, if the determination in S207 is YES (in the case of ECMVELNG ≧ CNG2), it is determined that the failure is not a short-term abnormality such as noise, and the process proceeds to S209, where the second failsafe flag fVELFS2 = 1. To do.

  The flowcharts of FIGS. 7 and 8 set the first failsafe flags fECMFS1 and fVELFS1 so that the failsafe process is started when the abnormal communication state continues for the first predetermined time (CNG1) or longer. When the abnormal state continues for a second predetermined time (CNG2) longer than the first predetermined time (CNG1), the second failsafe flags fECMFS2 and fVELFS2 are set so as to shift to further failsafe processing. It is.

  Here, since the first predetermined time (CNG1) is for determining a communication abnormality, for example, it is set to about 150 ms, whereas the second predetermined time (CNG2) is short such as noise. For example, it is set to about 2 seconds because it is not a time abnormality but a failure of the communication driver and harness / connector.

  Next, the fail-safe process at the time of communication abnormality detection (when the fail-safe flag is set) will be described with reference to the flowcharts of FIGS.

  In the main control of the ECM 10 of FIG. 5, in the first S111, it is determined whether or not the second failsafe flag fECMFS2 = 1. If NO, the process proceeds to S112, and if YES, the process proceeds to S115. In S112, it is determined whether or not the first failsafe flag fECFMS1 = 1. If YES, the process proceeds to S113.

  Therefore, when a communication abnormality occurs and the communication abnormality state continues for the first predetermined time (CNG1) or longer and the first failsafe flag fECMFS1 = 1, the process proceeds to S113 (instead of the processes of S11, S12, and S13). , S113, S114, and S116 are executed).

  In S113, instead of S11, the VEL target value (target valve operating angle) is fixed to a predetermined value M (for example, 200 ° CA) corresponding to a predetermined medium load. The calculated VEL target value is temporarily transmitted to VEL-C / U by communication means.

  In the next S114, the VEL actual value (actual valve operating angle) is fixed to the predetermined value M instead of S12.

  In the next S116, the VTC target value (target valve timing) is fixed to the most retarded value instead of S13. This is to ensure combustion stability during VEL fixation control. This is because when the valve timing is at the most retarded angle side, the valve overlap is reduced and the residual gas is reduced, thereby improving the combustion stability. After these, it progresses to S14 and performs the process of S14-S19.

  Further, if the communication abnormal state continues for the second predetermined time (CNG2) or longer and the second failsafe flag fECFMS2 = 1, the process proceeds to S115 (instead of the processes of S11, S12, and S13, the processes of S115 and S116) Run).

  In S115, instead of S11 and S12, both the VEL target value (target valve operating angle) and the VEL actual value (actual valve operating angle) are fixed to a predetermined value S (for example, 100 ° CA) corresponding to the minimum operating angle. Specifically, by shutting off the VEL power relay on the VEL-C / U side, the VEL duty to the VEL actuator is forcibly set to 0% and the minimum operating angle is controlled. The value is fixed to S. However, when the function for turning off the VEL power supply relay is on the ECM side, shut-off is executed on the ECM side.

  In the next S116, the VTC target value (target valve timing) is fixed to the most retarded value instead of S13. After these, it progresses to S14 and performs the process of S14-S19.

  In the main control at VEL-C / U20 in FIG. 6, in the first S211, it is determined whether or not the second failsafe flag fVELFS2 = 1. If NO, the process proceeds to S212, and if YES, the process proceeds to S214. move on. In S212, it is determined whether or not the first fail-safe flag fVELFS1 = 1. If YES, the process proceeds to S213.

  Accordingly, when a communication abnormality occurs and the communication abnormality state continues for the first predetermined time (CNG1) or longer and the first failsafe flag fVELFS1 = 1, the process proceeds to S213 (the process of S213 is replaced with the process of S21). Run).

  In S213, instead of S21 (instead of reading the VEL target value from the ECM), the VEL target value (target valve operating angle) is set in advance to the same value as the fixed value of the VEL target value and actual VEL value on the ECM side. The predetermined value M is fixed.

  Thereafter, the process proceeds to S22, and the valve operating angle is controlled so as to obtain the VEL target value (= predetermined value M) by executing the processes of S22 to S24.

  Further, when the communication abnormal state continues for the second predetermined time (CNG2) or longer and the second failsafe flag fVELFS2 = 1, the process proceeds to S214 (the process of S214 is executed instead of the process of S21 to S24). .

  In S214, the VEL power relay is shut off. As a result, the VEL duty to the VEL actuator is forced to 0%, and the valve operating angle is controlled to the minimum operating angle. Therefore, the VEL target value (target valve operating angle) and the VEL actual value (actual valve operating angle) are fixed to a predetermined value S corresponding to the minimum operating angle. However, when the function for turning off the VEL power supply relay is on the ECM side, shut-off is executed on the ECM side.

  Next, the time chart of FIG. 10 will be described.

  When a communication abnormality occurs, the values of the message counters VELECKCK and ECMVELCK no longer count up (counter deviation = 0), thereby detecting the occurrence of a communication abnormality.

  Here, the accelerator is depressed immediately before the occurrence of the communication abnormality, the VEL target value becomes large on the ECM side, and control is performed in accordance with the VEL target value on the VEL-C / U side. When the communication abnormality occurs, the actual VEL value is small.

  Then, on the ECM side, the VEL actual value cannot be recognized (the state where the small VEL actual value at the time of occurrence of the abnormality is held).

  Similarly, the VEL-C / U side is in a state where the VEL target value from the ECM cannot be recognized (a state where the VEL target value at the time of occurrence of abnormality is held).

  Therefore, when the first predetermined time (CNG1) has elapsed since the detection of the occurrence of the abnormality, the abnormality is determined, and on the ECM side, the VEL target value and the VEL actual value are fixed to a predetermined value M corresponding to a predetermined medium load. On the VEL-C / U side, the VEL target value is fixed to the same value as the predetermined value M set in advance.

  As a result, even if a communication abnormality occurs, the actual value of the valve operating angle recognized on the ECM side and the target value of the valve operating angle recognized on the VEL-C / U side are set to the same value, and the recognition shift is prevented. In addition, by setting the value to be fixed to a predetermined value corresponding to a predetermined medium load, a minimum operation (running) can be made possible.

  At this time, the valve timing is fixed to the most retarded angle side on the ECM side. As a result, the valve overlap is reduced and the residual gas is reduced, so that the combustion stability during the VEL fixing control is improved and the engine stall can be prevented.

  This state is continued until the second predetermined time (CNG2) elapses in the communication abnormality detection state. When the communication abnormality is resolved before the second predetermined time (CNG2) elapses, normal control is performed. Return. This is because a short-term data abnormality due to noise or the like is eliminated by data restoration, and therefore it is necessary to distinguish from a failure of a communication driver or a harness / connector.

  When the second predetermined time (CNG2) has elapsed in the communication abnormality detection state, the valve operating angle is controlled to the minimum operating angle by shutting off the VEL power supply relay. At this time, the VEL target value and the actual VEL value are set to a predetermined value S corresponding to the minimum operating angle on the ECM side, and the VEL target value (and the VEL execution value) are set to the same predetermined value M on the VEL-C / U side. Thereby, it is possible to accurately cope with a failure of the communication driver and the harness / connector.

  As described above, according to the present embodiment, the first and second control units (ECM10, VEL-C / U20) and the communication means (30) between them are provided, and the first control unit ( The ECM 10) calculates a target value of the valve operating angle of the intake valve and transmits it to the second control unit (VEL-C / U20), and the second control unit (VEL-C / U20) 1. The internal combustion engine control system controls the valve operating angle of the intake valve according to a target value from one control unit (ECM10), detects an actual value of the valve operating angle, and transmits the detected value to the first control unit (ECM10). In the variable valve control device, the first control unit (ECM10) detects a communication abnormality of the communication means (30). When a communication abnormality is detected, the actual value of the valve operating angle received from the second control unit (VEL-C / U20) is determined as a fail-safe process when a communication abnormality is detected. A fail safe means for fixing the communication means to the second control unit (VEL-C / U20), detecting a communication abnormality of the communication means (30), and detecting a communication abnormality. The fail-safe process includes fail-safe means for fixing the target value of the valve operating angle received from the first control unit (ECM10) to the same value (M) as the predetermined value. Even if a communication abnormality occurs, the actual value of the valve operating angle recognized by the first control unit (ECM10) and the second controller By setting the target value of the valve operating angle recognized by the remote unit (VEL-C / U20) to the same value, eliminating the discrepancy in recognition, and setting the fixed value to a predetermined value corresponding to a predetermined medium load , Minimum driving (running) can be made possible.

  Further, according to the present embodiment, each fail-safe means of the first and second control units (ECM10, VEL-C / U20) has a communication abnormality detection state by the communication abnormality detection means for a predetermined time (CNG2). When the above is continued, the fixed value is changed to a value corresponding to the minimum operating angle (S), so that it is possible to appropriately cope with a short-term communication abnormality such as noise.

  Further, according to the present embodiment, each fail-safe means of the first and second control units (ECM10, VEL-C / U20) has a communication abnormality detection state by the communication abnormality detection means in a first predetermined time. (CNG1) When it has continued for more than, the fail-safe process is started, and the communication abnormality detection state by the communication abnormality detection means has continued for a second predetermined time (CNG2) longer than the first predetermined time (CNG1) Sometimes, by changing the fixed value to a value corresponding to the minimum operating angle, it is possible to improve reliability by performing communication abnormality confirmation work, and short-term data abnormalities such as noise And a failure of the communication driver and harness / connector can be distinguished and dealt with appropriately.

  In addition, according to the present embodiment, the first control unit (ECM10) calculates a target value of the valve timing of the intake valve and controls the valve timing, and the first control unit (ECM10) The fail-safe means has a function to control the valve timing to the most retarded angle side as a fail-safe process when a communication abnormality is detected, thereby reducing the valve overlap and fixing the residual gas while the valve operating angle is fixed. By reducing, combustion stability can be improved and engine stall can be prevented.

  Further, according to the present embodiment, the first control unit (ECM10) calculates the target value of the valve timing of the intake valve and controls the valve timing. In calculating the target value of the valve timing, By having a function of limiting the target value of the valve timing in accordance with the actual value of the valve operating angle from the second control unit (VEL-C / U20), valve timing control and valve operating angle (and lift amount) It is possible to reliably prevent interference with the piston in connection with the control. In addition, a mechanical restriction by a stopper or the like is not necessary, and the control range of the variable valve operating device can be expanded, so that fuel consumption can be improved. In addition, it is possible to prevent a decrease in output, fuel consumption, and exhaust performance due to an increase in the valve recess depth of the piston as a countermeasure against interference.

  According to the present embodiment, the communication abnormality detection means provided in each control unit (ECM10, VEL-C / U20) counts up from the other control unit via the communication means at a predetermined cycle. By monitoring the value of the message counters (ECMVELCK, VELECKCK) to be transmitted, it is possible to make the communication simple and reliable by detecting the communication abnormality.

Engine system diagram showing an embodiment of the present invention Configuration diagram of variable valve gear Characteristic of valve lift with variable valve gear Configuration diagram of control system Flow chart of main control on the ECM side Flowchart of main control on the VEL-C / U side Flowchart of ECM communication error detection Flowchart of communication abnormality detection on the VEL-C / U side Explanatory drawing of message counter used to detect communication abnormality Time chart of ECM side and VEL-C / U side when communication abnormality is detected

Explanation of symbols

1 Engine 4 Intake valve 8 Exhaust valve 10 ECM (first control unit)
20 VEL-C / U (second control unit)
30 Communication Means 49 VEL Actuator 49S VEL Position Sensor 51 VTC Actuator 51S VTC Position Sensor

Claims (6)

A first control unit and a second control unit, and a communication means between them;
The first control unit calculates a target value of the valve operating angle of the intake valve, and transmits the target value to the second control unit;
The second control unit controls the valve operating angle of the intake valve according to the target value from the first control unit, detects an actual value of the valve operating angle, and transmits the actual value to the first control unit. In an engine variable valve controller,
In the first control unit, a communication abnormality detecting means for detecting a communication abnormality of the communication means, and an actual value of a valve operating angle received from the second control unit as a fail-safe process when a communication abnormality is detected are determined in advance. Fail-safe means for fixing to a predetermined value equivalent to a medium load,
In the second control unit, a communication abnormality detection means for detecting a communication abnormality of the communication means, and a target value of a valve operating angle received from the first control unit as a fail-safe process when a communication abnormality is detected are determined in advance. And a fail-safe means for fixing to the same value as the predetermined value.   Each fail-safe means of the first and second control units changes the fixed value when the communication abnormality detection state by the communication abnormality detection means continues for a predetermined time or longer, 2. The variable valve control apparatus for an internal combustion engine according to claim 1, wherein:   Each fail-safe means of the first and second control units starts the fail-safe process when the communication abnormality detection state by the communication abnormality detection means continues for a first predetermined time or more, and detects the communication abnormality. 3. The fixed value is changed to a value corresponding to a minimum operating angle when a communication abnormality detection state by means continues for a second predetermined time longer than the first predetermined time. The variable valve control apparatus for an internal combustion engine according to claim. The first control unit calculates a target value of the valve timing of the intake valve and controls the valve timing.
The fail-safe means of the first control unit has a function of controlling the valve timing to the most retarded angle side as fail-safe processing when a communication abnormality is detected. A variable valve control apparatus for an internal combustion engine as set forth in claim 1.   The first control unit controls the valve timing by calculating a target value of the valve timing of the intake valve, and when calculating the target value of the valve timing, the actual valve operating angle from the second control unit is calculated. The variable valve control apparatus for an internal combustion engine according to any one of claims 1 to 4, which has a function of limiting a target value of valve timing in accordance with a value.   The communication abnormality detecting means provided in each control unit detects a communication abnormality by monitoring the value of a message counter that is transmitted while counting up from the other control unit via the communication means at a predetermined cycle. The variable valve control apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein:

Images