• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A method for estimating the end-of-stroke positions of moving members of electromagnetic actuators for the actuation of intake and exhaust valves in internal combustion engines in which an actuator is coupled to a respective intake or exhaust valve and comprises a moving member actuated magnetically in order to control the movement of the valve, a sensor supplying a position signal representative of a current position of this moving member and a first and a second electromagnet disposed on opposite sides of the moving member, wherein this moving member can move between a first end-of-stroke position in which it is disposed in contact with the first electromagnet and a second end-of-stroke position in which it is disposed in contact with the second electromagnet. The method comprises the stages of checking whether the condition of stationary contact of the moving member exists and determining a magnitude correlated with this current position, if the stationary condition is verified.
    公开号:US20010006048A1
    申请号:US09/739,799
    申请日:2000-12-20
    公开日:2001-07-05
    发明作者:Nicola Lieto；Gilberto Burgio；Roberto Flora
    申请人:Magneti Marelli SpA；
    IPC主号:F01L9-04
    专利说明:
    [0001] The present invention relates to a method for estimating the end-of-stroke positions of moving members of electromagnetic actuators for the actuation of intake and exhaust valves in internal combustion engines. [0001] BACKGROUND OF THE INVENTION
    [0002] As is known, drive units are currently being tested in which the actuation of the intake and exhaust valves is managed by using actuators of electromagnetic type, which replace purely mechanical distribution systems (camshafts). [0002]
    [0003] These actuators in particular comprise a pair of electromagnets disposed on opposite sides of a moving ferromagnetic member connected to a respective intake or exhaust valve and held in a rest position by elastic members (for instance a spring and/or a torsion bar). The moving ferromagnetic member is actuated by applying a force generated by the electromagnets in order to be brought into contact alternatively with one or other of these electromagnets, so as to move the corresponding valve between a closed position and a position of maximum opening according to desired timings and trajectories. In this way, it is possible to actuate the valves according to optimum lift profiles in any operating condition of the engine, thereby substantially improving overall performance. [0003]
    [0004] Obtaining an actual increase in the efficiency of the engine is conditioned, however, by the precision of the systems and methods used for the control of the actuators. In order, in particular, accurately to control the force transmitted by the electromagnets to the moving member and thus the movement of the valve, it is indispensable to have an accurate measurement of the distances intervening between the moving member and the polar heads of one or the other electromagnet. As shown by way of example in FIG. 1, the force F that an electromagnet is able to transmit to the moving member depends, the current absorption being equal, in a highly non-linear manner on the distance D between the polar head of the electromagnet and the moving member. An error, even of a few microns, in the measurement of the distance D, in particular for low values of the latter, may therefore compromise the efficiency of the control and thus entail a substantial deterioration of the performance of the engine. [0004]
    [0005] This is a serious drawback, given that internal combustion engines are subject, during their use, to substantial temperature variations which cause expansions and/or contractions of the materials, especially of the metal parts. Consequently, even the polar heads of the electromagnets may expand or contract as a function of temperature, thereby affecting the measurement of the distances between these electromagnets and the moving member. [0005] SUMMARY OF THE INVENTION
    [0006] The object of the present invention is to provide a method for estimating the end-of-stroke positions of the moving member which makes it possible to remedy the above-mentioned drawbacks and, in particular, makes it possible to reduce the overall consumption of electrical power. [0006]
    [0007] The present invention therefore relates to a method for estimating the end-of-stroke positions of moving members of electromagnetic actuators for the actuation of intake and exhaust valves in internal combustion engines, in which an actuator is coupled to a respective intake or exhaust valve and comprises a moving member actuated magnetically in order to control the movement of the valve, a sensor supplying a position signal representative of a current position of this moving member and a first and a second electromagnet disposed on opposite sides of this moving member, wherein this moving member can move between a first end-of-stroke position in which it is disposed in contact with the first electromagnet and a second end-of-stroke position in which it is disposed in contact with the second electromagnet, which method is characterised in that it comprises the stages of: [0007]
    [0008] a) checking whether the moving member is in a condition of stationary contact; and [0008]
    [0009] b) determining a magnitude correlated with this current position, if the condition of stationary contact is verified. [0009] BRIEF DESCRIPTION OF THE DRAWINGS
    [0010] The invention is set out in further detail below with reference to an embodiment thereof, given purely by way of non-limiting example and made with reference to the accompanying drawings, in which: [0010]
    [0011] FIG. 1 is a graph relating to an electromagnetic actuator; [0011]
    [0012] FIGS. 2[0012] a and 2 b are lateral elevations, partly in cross-section, of an electromagnetic actuator and the corresponding intake or exhaust valve in a first and a second end-of-stroke position respectively;
    [0013] FIG. 3 is a simplified block diagram relating to the control method of the present invention; [0013]
    [0014] FIG. 4 is a flow diagram relating to the present method; and [0014]
    [0015] FIGS. 5 and 6 are graphs relating to curves of magnitudes of the present method. [0015] DETAILED DESCRIPTION OF THE INVENTION
    [0016] In FIGS. 2[0016] a and 2 b, an electromagnetic actuator 1 is coupled to an intake or exhaust valve 2 of an internal combustion engine. The actuator 1 comprises an oscillating arm 3 of ferromagnetic material having a first end hinged on a fixed support 4 so as to be able to rotate about a horizontal axis of rotation A perpendicular to a longitudinal axis B of the valve 2. A second end 5 of the oscillating arm 3 cooperates in contact, moreover, with an upper end of the valve 2 so as to impose an alternating movement in a direction parallel to the longitudinal axis B on this valve 2.
    [0017] The actuator [0017] 1 comprises a closing electromagnet 6 a and an opening electromagnet 6 b disposed on opposite sides of the body of the oscillating arm 3, in order to be able to act on command, in sequence or simultaneously, by exerting a net force on the oscillating arm 3 in order to cause it to rotate about the axis of rotation A.
    [0018] Moreover, a first and second elastic member, for instance a spring and a torsion bar, not shown for the sake of simplicity, act so that the oscillating arm [0018] 3 is maintained in a rest position in which it is equidistant from the polar heads of the closing and opening electromagnets 6 a and 6 b respectively.
    [0019] FIGS. 2[0019] a and 2 b also show a reference axis 9, oriented parallel to the longitudinal axis B of the valve, on which a coordinate of a point representative of the position of the oscillating arm 3 is shown (for instance the point of a lower edge 7 of the second end 2 which, at any moment, is located at the longitudinal axis B). In the following description, “position Z” is used to refer to this coordinate. Given that the end 5 normally acts in abutment against the upper end of the valve 2, the current position Z is also representative of the position of the valve 2.
    [0020] In FIG. 2[0020] a, in particular, the oscillating arm 3 is shown in a first end-of-stroke position or closed position, corresponding to a closed position value ZSUP on the reference axis 9. When in this position, the oscillating arm 3 is disposed in contact with the polar head of the closing electromagnet 6 a and therefore the position of the latter is represented by the closed position value ZSUP. It will be appreciated that, in this situation, the second end 5 of the oscillating arm 3 may be detached from the upper end of the valve 2 since this valve 2 reaches a limit position ZLIM in which it is kept closed. Even during a phase of detachment, however, the current position Z is representative of the actual position of the valve 2: values of the current position Z greater than the limit position ZLIM show that the valve 2 is closed and is exactly in the limit position ZLIM.
    [0021] In FIG. 2[0021] b, however, the oscillating arm 3 is shown in a second end-of-stroke position, i.e. a position of maximum opening, in which it is disposed in contact with the polar head of the opening electromagnet 6 b. This position of maximum opening, which corresponds to a maximum opening value ZINF on the reference axis 9, is therefore also representative of the position of the polar head of the closing electromagnet 6 a and also coincides with the position of maximum opening of the valve 2.
    [0022] In both FIG. 2[0022] a and FIG. 2b, moreover, the oscillating arm 3 is shown, in dashed lines, in the rest position, which is taken as the origin of the reference axis 9.
    [0023] As shown in FIG. 3, in a control system [0023] 10 of the actuator 1, a position sensor 11, of known type, supplies a position signal VZ representative of the current position Z of the oscillating arm 3 to an electronic control unit 12. The electronic control unit 12 is provided with a converter 13 which receives as input the position signal VZ, samples it at a predetermined sampling frequency and, in a manner known per se, supplies as output position values ZK correlated with sampling values VK assumed by the position signal VZ at each sampling moment K.
    [0024] The position values Z[0024] K acquired are stored in a memory 14, which, by means of a bus 15, is connected to a control unit 16 adapted to carry out procedures for the control of the operation of the engine. Moreover, the closed position value ZSUP and the maximum opening position value ZINF are also stored in the memory 14.
    [0025] With reference to FIG. 4, the method of the present invention provides that, following ignition of the engine (block [0025] 100), a first number N1, for instance 50, of position values ZK (block 110) is initially acquired.
    [0026] Subsequently, a test is carried out to check whether there is a condition of stationary contact of the valve [0026] 2, which exists when the oscillating arm 3 is held in the closed position ZSUP or the position of maximum opening ZINF (block 120). In particular, it is checked whether the difference between the maximum position value ZKMAX and the minimum position value ZKMIN among the N1 values of position ZK acquired is smaller than a predetermined range threshold Δ.
    [0027] If the outcome of the test is negative (output NO from the block [0027] 120), a new set of N1 values of position ZK is again acquired (block 110). If, however, the stationary conditions are verified (output YES from the block 120), a second number N2, for instance 200, of position values ZK are acquired (block 130), of which a mean value ZM (block 140) is then calculated according to the equation: Z M = 1 N 2  ∑ K = 1 2  Z K( 1 )
    [0028] It is then checked whether the oscillating arm [0028] 3 is in the closed position, verifying whether the mean value ZM is positive (block 150). If so (output YES from the block 150), i.e. if the oscillating arm 3 is in contact with the polar head of the closing electromagnet 6 a, the closed position ZSUP is set to ZM (block 155) and then memorised (block 160). If the mean value ZM is negative (output NO from the block 150) and therefore the oscillating arm 3 is in the position of maximum opening ZINF, in contact with the polar head of the opening electromagnet 6 b, the position of maximum opening ZINF is set to the mean value ZM (block 165) and memorised (block 170).
    [0029] Subsequently, it is checked whether stoppage of the engine has been requested (block [0029] 180). If so (output YES from the block 180), the estimation procedure is terminated (block 190); otherwise (output NO from the block 180), a set of N1 values of position ZK is again acquired (block 110).
    [0030] FIG. 5 shows, by way of example, a curve of the position values Z[0030] K (represented by points connected by a continuous line) and of the corresponding sampling values VK (shown by squares connected by dashed lines), as a function of the generic moment of sampling K; the first and the second number N1, N2 of position values acquired and the range threshold Δ are also shown.
    [0031] In practice, the end-of-stroke positions of the oscillating arm [0031] 3 (closed position and position of maximum opening) are estimated when it is recognised that the oscillating arm 3 is substantially stationary, i.e. when its actual position Z has not changed significantly for a time sufficient to acquire the first number of position values ZK. In this case, further position values ZK are acquired and their mean value ZM is calculated. In particular, the second number N2 of position values ZK acquired must be high enough so that any disturbances, for instance noise present in the position signal VZ, has no impact on the calculation of the mean value ZM. The mean value ZM is then memorised as a new closed position value ZSUP, if positive, or as a maximum opening position value ZINF, if negative. Given that, in each engine cycle, the valve 2 and therefore the oscillating arm 3 stop at least once in the closed position and in the position of maximum opening, both the values of the closed position ZSUP and of the position of maximum opening ZINF can be rapidly updated in succession. Moreover, the estimate of the end-of-stroke positions is repeated each time that the condition of stationary contact is verified, until the stoppage of the engine is requested.
    [0032] The estimation method as described has the following advantages. [0032]
    [0033] In the first place, it is possible to update the estimate of the end-of-stroke positions in real time, given that the estimation procedure is carried out each time that stationary contact conditions are detected. Consequently, a precise estimate of the positions of the polar heads of the closing and opening electromagnets [0033] 6 a and 6 b is also supplied in real time.
    [0034] It is therefore possible to obtain a correct measurement of the distance intervening between the polar heads of the electromagnets and the oscillating arm, irrespective of variations due to heat expansion. [0034]
    [0035] In particular, the method of the present invention may be advantageously used for instance in the case of the method for the control of electromagnetic actuators as disclosed in Italian Patent Application BO99A000594 of Nov. 5, 1999 filed in the name of the applicants. [0035]
    [0036] This Patent Application relates to the control of an electromagnetic actuator, substantially of the type of the actuator [0036] 1 described in FIGS. 2a and 2 b, to which reference will continue to be made. According to the method disclosed in the above-mentioned Application, a feedback control of the actual position Z and of an actual velocity V of the valve 2 is carried out, using, as the control variable, the net force applied by means of the opening and closing electromagnets 6 a and 6 b to the oscillating arm 3, which actuates this valve 2. For this purpose, by means of a model based on a dynamic system, an objective force value Fo to be exerted on the oscillating arm 3 is calculated as a function of an actual position, an actual velocity, a reference position and a reference velocity of the valve. The dynamic system is in particular described by the following matricial equation: [ Z . V . ] =[0 1 K / M B / M ]    [Z V] + [0 1 / M ]     F ( 2 )
    [0037] in which {dot over (Z)} and {dot over (V)} are the time derivatives of the actual position Z and of the actual velocity V respectively, F is the net force exerted on the oscillating arm [0037] 3, K is an elastic constant, B is a viscous constant and M is an equivalent total mass. In particular, the net force F and the actual position Z respectively represent an input and an output of the dynamic system.
    [0038] Moreover, the objective force value F[0038] o is calculated by the equation:
    [0039] in which N[0039] 1, N2, K1 and K2 are gains that may be calculated by applying well-known robust control techniques to the dynamic system represented by equation (2).
    [0040] Subsequently, the current values to be supplied to the closing and opening electromagnets [0040] 6 a and 6 b are calculated so that the net force exerted on the oscillating arm 3 has a value equal to the objective force value Fo.
    [0041] Clearly, given that the net force applied, as discussed above, is highly dependent on the actual distance intervening between the oscillating arm [0041] 3 and the polar heads of the closing and opening electromagnets 6 a and 6 b, the use of the present estimation method in the case described in the above-mentioned patent application makes it possible substantially to improve the accuracy and reliability of the control.
    [0042] It will be appreciated that modifications and variations may be made to the method as described, without departing from the scope of the present invention. [0042]
    [0043] In particular, the condition of stationary contact of the oscillating arm [0043] 3 (FIG. 4, block 120) could be evaluated in a different way. For instance, it is possible to check whether a minimum number NK of consecutive position values ZK are alternately greater than an upper limit position ZLSUP (oscillating arm 3 in the closed position) or lower than a lower limit position ZLINF (oscillating arm 3 in the position of maximum opening) as shown in FIG. 6. As an alternative, it is possible to verify whether the velocity of the oscillating arm is below a predetermined threshold, or whether the currents supplied to the closing or opening electromagnets 6 a and 6 b continue to be substantially constant.
    权利要求:
    Claims (7)
    [1" id="US-20010006048-A1-CLM-00001] 1. A method for estimating the end-of-stroke positions of moving members of electromagnetic actuators for the actuation of intake and exhaust valves in internal combustion engines, in which an actuator (1) is coupled to a respective intake or exhaust valve (2) and comprises a moving member (3) actuated magnetically in order to control the movement of the valve (2), a sensor (10) supplying a position signal (VZ) representative of a current position (Z) of this moving member (3) and a first and a second electromagnet (6 a, 6 b) disposed on opposite sides of this moving member (3), wherein this moving member (3) can move between a first end-of-stroke position (ZSUP) in which it is disposed in contact with the first electromagnet (6 a) and a second end-of-stroke position (ZINF) in which it is disposed in contact with the second electromagnet (6 b), which method is characterised in that it comprises the stages of:
    a) checking whether a condition of stationary contact of the moving member (3) exists (110, 120); and
    b) determining a magnitude (ZM) correlated with this current position (Z) (130, 140), if the condition of stationary contact is verified.
    [2" id="US-20010006048-A1-CLM-00002] 2. A method as claimed in
    claim 1 , characterised in that the stage a) of checking whether the condition of stationary contact exists comprises the stage of:
    a1) acquiring a first number (N1) of position values (ZK) correlated with sampling values (VK) of the position signal (VZ) at predetermined sampling moments (110).
    [3" id="US-20010006048-A1-CLM-00003] 3. A method as claimed in
    claim 2 , characterised in that the stage a) of checking whether the condition of stationary contact exists further comprises the stage of:
    a2) checking whether the difference between a maximum position value (ZKMAX) and a minimum position value (ZKMIN) is lower than a range threshold (D).
    [4" id="US-20010006048-A1-CLM-00004] 4. A method as claimed in
    claim 2 , characterised in that the stage a) of checking whether the condition of stationary contact exists further comprises the stage of:
    a3) checking whether the position values (ZK) acquired are greater than an upper limit position (ZLSUP),
    a4) checking whether the position values (ZK) acquired are lower than a lower limit position (ZLSUP).
    [5" id="US-20010006048-A1-CLM-00005] 5. A method as claimed in
    claim 1 , characterised in that the stage b) of determining a magnitude (ZM) comprises the stages of:
    b1) acquiring a second number (N2) of position values (ZK) correlated with sampling values (VK) of the position signal (VZ) at predetermined sampling moments (130); and
    b2) calculating a mean value (ZM) of the position values (ZK) acquired (140).
    [6" id="US-20010006048-A1-CLM-00006] 6. A method as claimed in
    claim 5 , characterised in that the stage b2) of calculating the mean value (ZM) is followed by the stages of:
    b3) determining whether the moving member (3) is in the first end-of-stroke position (150); and
    b4) determining whether the moving member (3) is in the second end-of-stroke position (150).
    [7" id="US-20010006048-A1-CLM-00007] 7. A method as claimed in
    claim 6 , characterised in that it further comprises the stages of:
    b5) setting a first end-of-stroke position value (ZSUP) to this mean value (ZM) if the moving member (3) is in the first end-of-stroke position (155).
    b6) setting a second end-of-stroke position value (ZINF) to this mean value (ZM) if the moving member (3) is in the second end-of-stroke position (165).
    类似技术:
    公开号 | 公开日 | 专利标题
    US6397797B1|2002-06-04|Method of controlling valve landing in a camless engine
    US8485148B2|2013-07-16|Method and device for controlling a hydraulic actuator
    US6681728B2|2004-01-27|Method for controlling an electromechanical actuator for a fuel air charge valve
    EP1167725B1|2004-02-25|Engine valve drive control apparatus and method
    US20020158218A1|2002-10-31|Control apparatus and method of electromagnetic valve
    EP1098072B1|2004-10-20|A method for the control of electromagnetic actuators for the actuation of intake and exhaust valves in internal combustion engines
    EP1934438B1|2010-08-18|Control apparatus and control method of electromagnetic drive valve operating mechanism
    JPH11148328A|1999-06-02|Device for detecting timing of solenoid driven opened or closed
    US6340007B2|2002-01-22|Method for estimating the end-of-stroke positions of moving members of electromagnetic actuators for the actuation of intake and exhaust valves in internal combustion engines
    Tai et al.2003|Control of an electromechanical actuator for camless engines
    US6938591B2|2005-09-06|Electromagnetically driven valve control apparatus and method
    US20020100439A1|2002-08-01|Control method for an electromagnetic actuator for the control of an engine valve
    US7878161B2|2011-02-01|Sliding mode control apparatus and adjusting method
    US6659422B2|2003-12-09|Control method for an electromagnetic actuator for the control of a valve of an engine from a rest condition
    US6920029B2|2005-07-19|Control method for an electromagnetic actuator for the control of a valve of an engine from an abutment condition
    US6591204B2|2003-07-08|Method and device for estimating magnetic flux in an electromagnetic actuator for controlling an engine valve
    EP1106790B1|2006-02-22|A method for the control of electromagnetic actuators for the actuation of intake and exhaust valves in internal combustion engines
    US6798636B2|2004-09-28|Method of estimating the effect of the parasitic currents in an electromagnetic actuator for the control of an engine valve
    US20030140875A1|2003-07-31|Method for estimating the position and speed of an actuator body in an electromagnetic actuator for controlling the valve of an engine
    US20010029913A1|2001-10-18|Method for regulation of currents during phases of stoppage in electromagnetic actuators, for actuation of intake and exhaust valves in internal-combustion engines
    JP4255426B2|2009-04-15|Valve clearance adjusting device and adjusting method
    JP2001159332A|2001-06-12|Control device for solenoid driven valve
    JP2001015329A|2001-01-19|Estimating device for valve clearance of electromagnetically driven valve
    同族专利:
    公开号 | 公开日
    US6340007B2|2002-01-22|
    BR0006536A|2001-10-30|
    ES2257995T3|2006-08-16|
    EP1132580A1|2001-09-12|
    ITBO990710D0|1999-12-23|
    DE60026228D1|2006-04-27|
    DE60026228T2|2006-11-23|
    EP1132580B1|2006-03-01|
    IT1311376B1|2002-03-12|
    ITBO990710A1|2001-06-23|
    BRPI0006536B1|2016-11-16|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FR2819931A1|2001-01-24|2002-07-26|Sagem|Electromagnetic valve opening/closing driver adjustment unit has drive units' two ends movement, with time/distance profile and sum of products compared and adjusted|US4957074A|1989-11-27|1990-09-18|Siemens Automotive L.P.|Closed loop electric valve control for I. C. engine|
    US5596956A|1994-12-16|1997-01-28|Honda Giken Kogyo Kabushiki Kaisha|Electromagnetically driven valve control system for internal combustion engines|
    US6176208B1|1997-07-03|2001-01-23|Nippon Soken, Inc.|Electromagnetic valve driving apparatus|
    DE19739840C2|1997-09-11|2002-11-28|Daimler Chrysler Ag|Method for controlling an electromagnetically actuated actuating device, in particular a valve for internal combustion engines|
    JPH11148328A|1997-11-12|1999-06-02|Fuji Heavy Ind Ltd|Device for detecting timing of solenoid driven opened or closed|
    EP0973178B1|1998-07-17|2004-09-29|Bayerische Motoren Werke Aktiengesellschaft|Method for controlling the motion of an armature of an electromagnetic actuator|
    JP3846070B2|1998-10-29|2006-11-15|トヨタ自動車株式会社|Control device for electromagnetically driven valve|DE10205383B4|2002-02-09|2007-04-12|Bayerische Motoren Werke Ag|Method for controlling the movement of an armature of an electromagnetic actuator|
    DE10216759A1|2002-04-16|2004-02-19|Lsp Innovative Automotive Systems Gmbh|Stationary position estimation method for electromagnetic drive for operation of IC engine valve using recursive low-pass filtering of actual position for updating previously estimated stationary position|
    US6698408B2|2002-07-10|2004-03-02|Eaton Corporation|Position control strategy EGR valve actuator|
    US20050076866A1|2003-10-14|2005-04-14|Hopper Mark L.|Electromechanical valve actuator|
    法律状态:
    2000-12-20| AS| Assignment|Owner name: MAGNETI MARELLI S.P.A., ITALY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:DI LIETO, NICOLA;BURGIO, GILBERTO;FLORA, ROBERTO;REEL/FRAME:011388/0512 Effective date: 20001204 |
    2002-01-03| STCF| Information on status: patent grant|Free format text: PATENTED CASE |
    2005-07-22| FPAY| Fee payment|Year of fee payment: 4 |
    2009-06-29| FPAY| Fee payment|Year of fee payment: 8 |
    2013-03-11| FPAY| Fee payment|Year of fee payment: 12 |
    优先权:
    申请号 | 申请日 | 专利标题
    IT1999BO000710A|IT1311376B1|1999-12-23|1999-12-23|METHOD FOR ESTIMATING THE END OF STROKE POSITIONS OF MOBILE BODIES ELECTROMAGNETIC ACTUATORS FOR THE OPERATION OF INTAKE VALVES|
    ITBO99A000710||1999-12-23||
    ITBO99A0710||1999-12-23||
    [返回顶部]