JP2008196389A - Valve position learning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve position learning device capable of precisely learning a full open position and a full close position of a valve. <P>SOLUTION: A control means 7 makes first predetermined drive current flow to a motor 53 and learns opening of the valve 52 as the full close position when predetermined time elapses under a condition where valve opening does not change, and makes second predetermined drive current flow to the motor 53 and learns opening of the valve 52 as the full open position when predetermined time elapses under a condition where valve opening does not change. The control means 7 learns the full close position again by third predetermined drive current which is larger than the first predetermined drive current and learns the full open position again by fourth predetermined drive current which is larger than the second predetermined drive current when the same determines any of the full close position, the full open position and difference between the full close position and the full open position is not kept in a predetermined range set respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a valve position learning device for learning a fully closed position and a fully open position of a valve driven by a motor.

  2. Description of the Related Art Conventionally, an EGR device that circulates part of exhaust gas to intake air is known as a device that reduces NOx contained in engine exhaust.

  In the EGR device, an EGR valve is provided in an EGR passage that connects the intake passage and the exhaust passage, and the flow rate of the exhaust gas circulating through the EGR passage is adjusted.

  Here, for example, in an EGR valve that controls the EGR valve opening degree (EGR flow rate), in order to accurately control the EGR flow rate, it is important to accurately detect the EGR valve position with a position sensor. Become.

  For this purpose, as shown in FIG. 4, for example, as shown in FIG. 4, a constant driving current is supplied to the motor after the power is turned on, so that the EGR valve is fully closed (step S41) and fully opened (step A method is known in which the output of the position sensor at that time is learned by making a 0% opening (step S42) and a 100% opening (step S44).

  Patent Document 1 proposes a failure determination method in which, in initial learning of the throttle opening, when the throttle valve position (opening) does not change, an abnormality is determined and the initial learning is terminated.

JP 2000-64887 A

  However, when performing position learning as shown in FIG. 4, the motor and the EGR valve are driven with a driving force that overcomes the friction applied to the EGR valve, and the EGR valve is accurately brought into the fully closed position and the fully opened position. However, due to the adhesion of small foreign matter to the EGR valve and the accumulation of carbon, the friction applied to the EGR valve temporarily increases, learning at the wrong position, and EGR control is not performed properly. A valve failure may be misdiagnosed.

  That is, conventionally, in order to fully close (or fully open) the EGR valve, a predetermined driving current is supplied to the motor, and the position when the EGR valve stops against the valve seat (or stopper, etc.) is fully closed. It was learned as a position (or fully open position). However, if carbon or the like accumulates on the EGR valve and friction increases, the EGR valve stops before it hits the valve seat, etc. when a predetermined drive current is passed, and the stop position is mistakenly set to the fully closed position. There is a possibility that it may be judged as mislearning as a (or fully open position) or a failure of the EGR valve.

  Further, in Patent Document 1, an abnormality is determined when the valve position (opening) does not change, and erroneous learning at the wrong valve position cannot be determined, so that the valve position can be accurately learned. There wasn't.

  Therefore, an object of the present invention is to provide a valve position learning device that can solve the above-described problems and can accurately learn the fully open position and the fully closed position of the valve.

  In order to achieve the above object, the present invention provides a valve provided in a gas passage for adjusting the flow rate of the gas passage, a motor for driving the valve, and a valve opening for detecting the opening position of the valve. Degree detection means and control means for inputting the valve opening detected by the valve opening detection means and outputting a drive current to the motor. In the valve position learning device for learning the closed position, the control means supplies a first predetermined driving current to the motor to fully close the valve, and the valve is input from the valve opening degree detecting means. Monitors the opening, learns the valve opening at that time as a fully closed position when a predetermined time has elapsed with the input valve opening substantially unchanged, and A second predetermined drive current is supplied to the motor to fully open and the valve opening input from the valve opening detection means is monitored, and the input valve opening is not substantially changed for a predetermined time. When the time has elapsed, the valve opening at that time is learned as a fully opened position, and the control means is further configured to determine whether the fully closed position, the fully opened position, or the difference between the fully opened position and the fully closed position is: When it is determined that it does not fall within the predetermined normal range set for each, the learning of the fully closed position is performed again with a third predetermined drive current larger than the first predetermined drive current, and the second The full-open position is learned again with a fourth predetermined drive current larger than the predetermined drive current.

  Preferably, the control means performs learning of the fully closed position and the fully open position again with the third and fourth predetermined drive currents, and then performs the fully closed position, the fully open position, and the fully open position and the fully open position. When it is determined that any of the differences from the closed position does not fall within the predetermined normal range, the learning of the fully closed position is performed again with a fifth predetermined drive current larger than the third predetermined drive current. And the learning of the fully open position is performed again with a sixth predetermined drive current larger than the fourth predetermined drive current.

  Preferably, the control means performs learning of the fully closed position and the fully opened position again with the fifth and sixth predetermined drive currents, and then performs the fully closed position, the fully opened position, and the fully opened position and the fully opened position. When it is determined that any of the differences from the closed position does not fall within the predetermined normal range, the fully closed position, the fully open position, and the difference between the fully open position and the fully closed position are all within the predetermined normal range. The learning for the fully closed position and the fully opened position are repeated until the position is within the range, and every time the fully closed position and the fully opened position are learned, the drive used for learning the fully closed position and learning the fully opened position is repeated. Each current is set large.

  Preferably, the control means repeats learning of the fully closed position and learning of the fully opened position a predetermined number of times, and then determines whether the fully closed position, the fully opened position, or the difference between the fully opened position and the fully closed position is When it is determined that the value does not fall within the predetermined normal range set for each, it is determined that the valve, the motor, and the valve opening degree detection means are out of order.

  According to the present invention, an excellent effect that the fully open position and the fully closed position of the valve can be accurately learned is exhibited.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  The valve position learning device according to the present embodiment is applied to, for example, an EGR valve of a vehicle.

  First, the schematic structure of the vehicle will be described with reference to FIG.

  As shown in FIG. 1, a vehicle 1 includes an engine (a diesel engine in the illustrated example) 2 having a plurality of cylinders, an intake pipe 3 for supplying intake air (fresh air) to the engine 2, An exhaust pipe 4 for exhausting the exhaust gas, an exhaust gas recirculation device (hereinafter referred to as an EGR device) 5 for circulating a part of the exhaust gas in the exhaust pipe 4 to the intake pipe 3, and an air pressure for the engine 2 The supercharger 6, an electronic control device (hereinafter referred to as ECM) 7 for controlling the engine 2 and the EGR device 5, and a battery 11 for supplying electric power to the ECM 7 and the like.

  The engine 2 includes a combustion chamber 23 partitioned by a cylinder 21 and a piston 22, a fuel injection valve 24 for injecting and supplying fuel to the combustion chamber 23, and a cooling water passage (not shown) for circulating cooling water. An attached engine water temperature sensor 25 and a cam sensor 26 for detecting an angle of a cam shaft (not shown) are provided.

  In the intake pipe 3, in order from the upstream side, an air cleaner 31, an intake air temperature (IAT) sensor 32, an intake air flow rate (MAF) sensor 33, a compressor 64 of a supercharger 6 to be described later, and intake air for restricting the intake air. A throttle valve device 34 is provided. An intake manifold (not shown) is provided at the downstream end of the intake pipe 3, and the intake manifold is connected to the combustion chamber 23 of each cylinder.

  The intake throttle valve device 34 includes an intake throttle valve 341, an intake throttle drive motor 342 for driving the intake throttle valve 341, and an intake throttle position sensor 343 for detecting the opening position of the intake throttle valve 341. Have.

  An exhaust manifold 41 is provided at the upstream end of the exhaust pipe 4, and the exhaust manifold 41 is connected to each combustion chamber 23. The exhaust pipe 4 downstream of the exhaust manifold 41 is provided with a turbine 61, an exhaust aftertreatment device 42, and an exhaust throttle 43, which will be described later, in order from the engine side.

  The supercharger 6 of this embodiment is a variable capacity turbocharger, and includes a turbine 61 having a turbo vane 62, a VGS turbo controller 63 for controlling the opening position of the turbo vane 62, and a compressor driven by the turbine 61. 64. The turbine 61 includes a vane position sensor (not shown) for detecting the opening position of the turbo vane 62.

  The EGR device 5 includes an EGR pipe 51 that forms a gas passage for communicating the intake pipe 3 and the exhaust pipe 4, and a valve (hereinafter referred to as EGR) that is provided in the EGR pipe 51 and adjusts the flow rate of the EGR pipe 51. A valve 52), a motor 53 for opening and closing the EGR valve 52 (in this embodiment, a DC motor), and a valve opening degree detecting means (hereinafter referred to as an EGR position sensor) for detecting the opening position of the EGR valve 52. 54).

  The EGR pipe 51 has an upstream end connected to the exhaust pipe 4 upstream of the turbine 61 and a downstream end connected to the intake pipe 3 downstream of the intake throttle valve 341.

  As shown in FIG. 2, the EGR pipe 51 is provided with a housing 55 that defines a passage 57-59 for circulating exhaust gas.

  Specifically, the housing 55 has an intermediate passage 57 that extends vertically and has a valve seat 56 provided in the upper and lower intermediate portions, an inflow passage 58 that extends rightward from the lower portion of the intermediate passage 57, and the intermediate passage 57. And an outflow passage 59 extending to the left from the upper part.

  The EGR valve 52 abuts and separates from the valve seat 56 of the intermediate passage 57 from below to open and close the intermediate passage 57, and extends upward from the valve body 521 through the inner wall of the intermediate passage 57. And a valve shaft 522. A return spring 523 for urging the EGR valve 52 upward (closed side) is attached to the upper part of the valve shaft 522 via a retainer 524.

  The housing 55 is provided with a bush portion 551 that is positioned above the valve seat 56 and supports the valve shaft 522 of the EGR valve 52 so as to be movable up and down (movable up and down). The bush portion 551 serves as a stopper for restricting the fully opened position of the EGR valve 52, and when the EGR valve 52 moves downward to the fully opened position, a retainer 524 attached to the EGR valve 52 comes into contact with the bush 551. Yes.

  A motor 53 is attached to the upper portion of the housing 55. The motor 53 has an output shaft (not shown) that moves up and down, and the lower end of the output shaft engages with the upper end of the valve shaft 522 of the EGR valve 52. As the motor 53, a linear step motor or the like can be considered.

  For example, the motor 53 is housed in a casing 531 and includes a stator (not shown) formed by winding a coil around a core, and a shaft hole that is rotatably provided inside the stator and has a female screw cut. And a rotor (not shown) having a male screw that is screwed into a shaft hole of the rotor, and an output shaft extending downward.

  In addition, the motor 53 is not limited to this, Various things can be considered.

  A socket 532 for connecting the motor 53 to the ECM 7 is provided on the upper portion of the casing 531, and the stator coil and the EGR position sensor 54 are connected to the socket 532, respectively.

  By passing a drive current in a predetermined direction through the coil of the motor 53, the rotor rotates and the output shaft moves downward, the valve body 521 is separated from the valve seat 56, and the opening degree of the EGR valve 52 is increased. On the other hand, when an electric current is passed through the coil in the reverse direction, the output shaft moves upward, the valve body 521 approaches the valve seat 56, and the opening degree of the EGR valve 52 decreases.

  For example, the EGR position sensor 54 (see FIG. 1) is attached to the valve shaft 522 of the EGR valve 52 (or the output shaft of the motor 53), and detects the amount of movement of the valve shaft 522 in the axial direction (vertical direction). A linear potentiometer can be considered.

  Returning to FIG. 1, the vehicle 1 of the present embodiment is provided with a valve position learning device 9 for learning the fully open position and the fully closed position detected by the EGR position sensor 54.

  The valve position learning device 9 is a control for inputting the EGR valve 52, the motor 53, the EGR position sensor 54, and the valve opening detected by the EGR position sensor 54 and outputting a drive current to the motor 53. It is comprised with ECM7 which makes a means.

  The ECM 7 includes various sensors such as an EGR position sensor 54, a cam sensor 26, an intake throttle position sensor 343, an engine water temperature sensor 25, an intake air flow rate sensor 33, an intake air temperature sensor 32, an accelerator opening sensor 12, and a vane position sensor (not shown). Are connected, and the detection values of these sensors are input.

  The ECM 7 is connected to actuators such as the motor 53 of the EGR device 5, the intake throttle drive motor 342, the VGS turbo controller 63 of the supercharger 6, and the exhaust throttle 43, and outputs control signals to these actuators.

  The ECM 7 of this embodiment obtains a target EGR rate (that is, a target opening position of the EGR valve 52) from the operating state of the engine 2 and the like, and inputs from the EGR position sensor 54 so as to set the EGR valve 52 to the target opening position. The motor 53 of the EGR device 5 is feedback-controlled based on the detected opening position.

  Next, the operation of the valve position learning device 9 of this embodiment will be described.

  In this embodiment, in order to improve the accuracy of the valve position, when learning the fully closed position and the fully open position of the EGR valve 52, the motor 53 is operated with a constant drive current to detect the abutting position of the EGR valve 52. Then, it is determined whether or not the abutting position is within a normal range, and if the accurate position cannot be detected at the first time, the learning operation is repeated and the previous learning operation is repeated. The learning operation is performed with the drive current higher than in the above case.

  That is, the ECM 7 supplies the first predetermined drive current to the motor 53 to fully close the EGR valve 52 and monitors the valve opening input from the EGR position sensor 54, and the input valve opening is substantially equal. When a predetermined time elapses in a state where there is no change, the valve opening at that time is learned as a fully closed position, and a second predetermined drive current is supplied to the motor 53 to fully open the EGR valve 52 and the EGR position The valve opening input from the sensor 54 is monitored, and when a predetermined time elapses with the input valve opening substantially unchanged, the valve opening at that time is learned as a fully open position.

  Here, the first predetermined driving current and the second predetermined driving current are set based on the friction in a state where no soot or foreign matter adheres to the EGR valve 52, for example, a state immediately after the assembly of the EGR device 5 It is set based on.

  Further, when the ECM 7 determines that any one of the fully closed position, the fully opened position, and the difference between the fully opened position and the fully closed position does not fall within a predetermined normal range set for each of them, The fully closed position is learned again with a third predetermined drive current larger than the current, and the fully opened position is learned again with a fourth predetermined drive current larger than the second predetermined drive current.

  Here, the predetermined normal range is, for example, set based on the fully closed position and the fully opened position measured when the EGR device 5 is assembled in consideration of a mechanical error or the design value dimension. It is conceivable that the value is set in consideration of the tolerance.

  As described above, in this embodiment, when the position learning is not accurately performed, the learning is repeated again, and at that time, the driving force of the EGR valve 52 is increased compared with the previous learning operation, thereby temporarily Thus, the EGR valve 52 can be driven with a driving force that overcomes an increase in friction, and the valve position can be accurately learned.

  Here, it can be considered that there is no problem if the driving force is sufficiently increased from the beginning so that the friction of the EGR valve 52 temporarily rises without causing any problem. If it is too large, the impact force applied to the EGR valve 52 and the valve seat 56 at the time of abutting will increase, which may cause other problems such as reduced reliability and sag. It is important to increase the driving force only when necessary.

  Next, an example of a flow by the valve position learning device 9 of the present embodiment will be described based on FIG.

  The flow shown in FIG. 3 is executed by the ECM 7 when the ignition key is turned on, for example, when the engine is started.

  First, in step S1, the ECM 7 drives the motor 53 with a first predetermined driving current (Duty A% in FIG. 3) which is a fixed current value, and moves the valve body 521 of the EGR valve 52 upward (closed side). And) until the valve seat 56 that defines the fully closed position is reached.

  In step S2, the ECM 7 monitors the detection signal (voltage value) input from the EGR position sensor 54, and stores the voltage value X0 when the input voltage value is a constant value for a predetermined time. % Open position (fully closed position).

  In step S3, the ECM 7 drives the motor 53 with a second predetermined driving current (Duty B% in FIG. 3) that is a fixed current value, and moves the valve body 521 of the EGR valve 52 downward (to the open side). The retainer 524 attached to the valve shaft 522 is moved until it hits the bush portion 551 that defines the fully open position.

  In step S4, the ECM 7 monitors the detection signal (voltage value) input from the EGR position sensor 54, and stores the voltage value Y0 when the input voltage value is a constant value for a predetermined time. % Open position (fully open position).

  In step S5, the ECM 7 determines whether or not the stored X0 and Y0 and the value obtained by subtracting X0 from Y0 (Y0-X0) are within a predetermined normal range determined for each X0, Y0, Y0-X0. Judging.

  When all of X0, Y0, and Y0-X0 fall within each normal range, the ECM 7 performs normal control. For example, the ECM 7 calibrates the detection signal (opening position of the EGR valve 52) of the EGR position sensor 54 using the stored X0 and Y0, and feedback-controls the motor 53.

  On the other hand, when at least one of X0, Y0, and Y0-X0 is not within the normal range, the ECM 7 returns to step S1 and performs steps S1 to S5 again (second time).

  However, when performing Step S1 to Step S4 for the second time, the ECM 7 sets the fixed current value that flows to the motor 53 in Step S1 to a third predetermined drive that is larger than the first predetermined drive current (Duty A (%)). Current (Duty A1 (%)). Further, the ECM 7 sets the fixed current value that flows to the motor 53 in the second step S4 to the fourth predetermined drive current (Duty B1 (%)) that is larger than the second predetermined drive current (Duty B (%)). To do.

  When at least one of X0, Y0, and Y0-X0 is not within each normal range in the second step S5, the ECM 7 returns to step S1 again and performs steps S1 to S5 again (3) Second time).

  In the third step S1, the ECM 7 sets the fixed current value that flows to the motor 53 to a fifth predetermined drive current (Duty A2 (%)) that is larger than the third predetermined drive current (Duty A1 (%)). . In step S4 for the third time, the ECM 7 sets a fixed current value to be supplied to the motor 53 to a sixth predetermined drive current (Duty B2 (%)) larger than the fourth predetermined drive current (Duty B1 (%)). And

  As described above, the ECM 7 of the present embodiment again learns the fully closed position and the fully open position with the third predetermined drive current (Duty A1 (%)) and the fourth predetermined drive current (Duty B1 (%)). When it is determined that the fully closed position, the fully open position, or the difference between the fully open position and the fully closed position does not fall within the predetermined normal range, the third predetermined drive current (Duty A1 (% )) Greater than the fifth predetermined drive current (Duty A2 (%)), the learning of the fully closed position is performed again, and the sixth predetermined drive current greater than the fourth predetermined drive current (Duty B1 (%)) The fully open position is learned again with the drive current (Duty B2 (%)).

  Further, the ECM 7 performs learning of the fully closed position and the fully open position again with the fifth predetermined drive current (Duty A2 (%)) and the sixth predetermined drive current (Duty B2 (%)), and then fully closed. Position, fully open position, and the difference between fully open position, fully open position, and fully open position and fully closed position when it is determined that the difference between fully open position and fully open position does not fall within the specified normal range. Until all of the above are within the predetermined normal range, the learning of the fully closed position and the learning of the fully open position are repeated, and the learning of the fully closed position and the fully open position are repeated each time learning of the fully closed position and the fully open position is repeated. The drive current used for learning is sequentially increased.

  For example, a predetermined current value may be added to the drive current used for learning each time learning is repeated.

  In this way, learning is performed while increasing the drive current until all of the fully closed position, the fully open position, and the difference between the fully open position and the fully closed position detected by the EGR position sensor 54 fall within a predetermined normal range. By repeating, even when a soot or the like adheres to the EGR valve 52, the fully opened position and the fully closed position of the EGR valve 52 can be learned accurately.

  Further, the ECM 7 of the present embodiment repeats learning of the fully closed position and learning of the fully opened position a predetermined number of times, and then each of the fully closed position, the fully opened position, and the difference between the fully opened position and the fully closed position is When it is determined that it does not fall within the set predetermined normal range, it is determined that the EGR valve 52, the motor 53, and the EGR position sensor 54 are out of order.

  Thus, in the present embodiment, by setting an upper limit on the number of repetitions of learning, a failure can be detected when learning cannot be performed, such as when the EGR position sensor 54 is disconnected.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  In the above-described embodiment, the example of the EGR valve 52 has been described. However, the present invention is not limited to this, and the valve control of the intake throttle valve 341 attached to the intake pipe 3, the exhaust throttle 43 attached to the exhaust pipe 4, and the turbo vane. In the position learning for control 62, there is a problem that the valve sticks in the same manner as the EGR valve 52, and this problem is solved by the same method as the EGR valve 52 using the valve position learning device of the present invention. can be solved.

  Further, in the above-described embodiment, it is determined whether or not a failure occurs when the repetition of learning reaches a predetermined number of times. However, the present invention is not limited to this, and the drive current for fully closed learning and / or fully opened learning is predetermined. You may make it judge whether it is a failure when it is more than an upper limit electric current.

FIG. 1 is a schematic diagram of a valve position learning device and a vehicle according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the EGR device of the present embodiment. FIG. 3 shows an example of a flow by the valve position learning device of the present embodiment. FIG. 4 shows a conventional valve position learning flow.

Explanation of symbols

7 ECM (control means)
9 Valve position learning device 51 EGR passage (gas passage)
52 EGR valve (valve)
53 Motor 54 EGR position sensor (valve opening detection means)

Claims (4)

A valve provided in the gas passage for adjusting the flow rate of the gas passage, a motor for driving the valve, a valve opening degree detecting means for detecting the opening position of the valve, and a valve opening degree detecting means Valve position learning for learning a fully open position and a fully closed position detected by the valve opening degree detecting means, and a control means for outputting a driving current to the motor while inputting the valve opening degree detected by the valve In the device
The control means supplies a first predetermined drive current to the motor so as to fully close the valve, and monitors the valve opening inputted from the valve opening detecting means. When a predetermined time elapses in a state that does not substantially change, the valve opening at that time is learned as a fully closed position, and a second predetermined drive current is supplied to the motor to fully open the valve and the valve The valve opening input from the opening detection means is monitored, and when the input valve opening does not substantially change and a predetermined time has elapsed, the valve opening at that time is learned as a fully open position,
Further, when the control means determines that any one of the fully closed position, the fully opened position, and the difference between the fully opened position and the fully closed position does not fall within a predetermined normal range set for each of them, The fully closed position is learned again with a third predetermined drive current greater than the first predetermined drive current, and the fully open position is detected with a fourth predetermined drive current greater than the second predetermined drive current. A valve position learning apparatus characterized by performing position learning again.   The control means performs learning of the fully closed position and the fully opened position again with the third and fourth predetermined drive currents, and then performs the fully closed position, the fully opened position, and the fully opened position and the fully closed position. When it is determined that any one of the differences does not fall within the predetermined normal range, the fully closed position is learned again with a fifth predetermined drive current larger than the third predetermined drive current, and The valve position learning device according to claim 1, wherein learning of the fully opened position is performed again with a sixth predetermined drive current larger than the fourth predetermined drive current. The control means performs learning of the fully closed position and the fully opened position again with the fifth and sixth predetermined drive currents, and then performs the fully closed position, the fully opened position, and the fully opened position and the fully closed position. When it is determined that one of the differences is not within the predetermined normal range,
The fully closed position, the fully open position, and the difference between the fully open position and the fully closed position are repeated until learning of the fully closed position and learning of the fully open position until all of the differences are within the predetermined normal range. 3. The valve position learning device according to claim 2, wherein each time the learning of the closed position and the fully opened position is repeated, the driving current used for learning the fully closed position and the fully opened position is set to be large.   The control means repeats learning of the fully closed position and learning of the fully opened position a predetermined number of times, and then each of the fully closed position, the fully opened position, and the difference between the fully opened position and the fully closed position is 4. The valve position learning apparatus according to claim 3, wherein when it is determined that the set value does not fall within the predetermined normal range, it is determined that the valve, the motor, and the valve opening degree detection means are out of order.

Images