JP6476649B2 - Variable valve system, internal combustion engine, and control method for variable valve system - Google Patents

Description

  The present invention detects the wear of the cotter (valve stop ring) that fixes the valve spring holder over time from the behavior of the intake and exhaust valves when the vehicle is running, and prevents the intake and exhaust valves from falling into the combustion chamber. The present invention relates to a variable valve system, an internal combustion engine, and a control method for the variable valve system.

  In the conventional diesel engine, the opening / closing operation of the intake / exhaust valve for intake into the cylinder and exhaust from the cylinder is driven by the camshaft. Since this camshaft rotates in synchronization with the rotation of the engine, the opening and closing timing of the intake / exhaust valve is always constant on the crank angle base.

  For this cam drive system, in order to be able to arbitrarily set the opening / closing timing and lift amount of the intake / exhaust valve according to the operating state of the engine, there is no special cam mechanism, that is, the intake / exhaust valve open / close A valve drive device for a so-called camless type internal combustion engine that controls opening / closing of an intake / exhaust valve using fluid pressure such as hydraulic pressure instead of a camshaft has been proposed (for example, see Patent Document 1).

  As shown in FIG. 1, in such a hydraulically driven variable valve system 1 of a valve drive apparatus for an internal combustion engine, the valve 4 of the intake / exhaust valve is opened by supplying high-pressure hydraulic oil to the hydraulic control chamber 18. The valve 4 is supplied via the hydraulic piston 4c. That is, when the valve 4 is opened, the first operation valve (actuator) 15a is operated, and the high-pressure hydraulic oil boosted by the hydraulic pump 11 is sent to the hydraulic control chamber 18 through the flow path A. The valve shaft 4b is pushed down against the urging force of the valve spring 8 by hydraulic pressure to open the valve, and when the valve is closed, the second operating valve 15b is operated, and the high-pressure hydraulic fluid is supplied from the hydraulic control chamber 18 to the flow path of the hydraulic pipe 21. By letting it escape through B, the hydraulic pressure in the hydraulic control chamber 18 is lowered and the valve shaft 4b is pushed up by the urging force of the valve spring 8 to close the valve.

  On the other hand, when transferring the energy in the hydraulic control chamber to the intake / exhaust valve, in order to reduce the seating impact force applied to the intake / exhaust valve when the valve is closed, for example, the piston is operated by fluid pressure, and the intake / exhaust by the piston is performed. In a valve drive system for an internal combustion engine that lifts a valve such as a valve and opens the valve, and releases the fluid pressure and closes the valve, the fluid pressure is applied to the piston so that the piston is There has been proposed a valve drive apparatus for an internal combustion engine provided with a fluid pressure releasing means for reducing the fluid pressure applied to the piston immediately before reaching the stroke (see, for example, Patent Document 2).

  An operation example of the hydraulic intake / exhaust valve using the valve drive device of the internal combustion engine is shown by a solid line in FIG. 4, and an intake / exhaust valve operation in the cam drive is also shown by a dotted line. FIG. 5 shows the valve speed when the exhaust valve is closed at this time. As can be seen from FIG. 5, in the hydraulically driven variable valve system, the speed of the intake / exhaust valve at the time of closing is reduced to reduce the seating impact force, but the valve closing speed at the time of sitting is still higher than that of the cam drive. high. Therefore, there is a concern that the intake / exhaust valve may fall into the combustion chamber and the engine may be seriously damaged due to breakage of the umbrella portion of the intake / exhaust valve or wear of the protrusion inside the cotter over time. .

  On the other hand, regarding the control of the valve drive device of the internal combustion engine, for example, the differential pressure before and after the valve at the valve opening timing is calculated, the valve thrust required for the set valve lift amount is calculated, and the necessary high-pressure working fluid is calculated. And a control device that determines a required high-pressure working fluid charging period based on a map prepared in advance and controls the opening and closing of the valve based on the high-pressure hydraulic fluid charging period and charging period. A valve control system has been proposed (see, for example, Patent Document 3).

  In the valve opening control in this variable valve control system, the amount of high-pressure hydraulic oil charged into the hydraulic control chamber differs depending on the operating state of the engine, so the amount of energy required depends on the operating state and the target lift amount. An indication pulse of the period calculated and extracted from the map for the required amount of energy and hydraulic oil pressure is sent to the actuator.

  In other words, the amount of energy required to open the intake / exhaust valve is calculated from the cylinder pressure and intake / exhaust port pressure applied to the umbrella of the valve body of the intake / exhaust valve, the reaction force of the valve spring, and the attractive force of the permanent magnet. The high-pressure hydraulic oil supply amount and the drive pulse application period to the actuator are determined according to the hydraulic oil pressure. At this time, the in-cylinder pressure and the intake / exhaust port pressure are values that change from moment to moment depending on the engine operating state, but the reaction force by the valve spring and the attractive force by the permanent magnet do not depend on the operating state of the engine and It depends on the value.

  However, if wear occurs in the cotter (valve stop ring) that is fitted in the groove provided near the upper end of the valve shaft of the valve and fixes the valve spring receiver, the cotter and valve spring in the closed state are The locked valve spring receiver (spring upper seat) moves in the direction approaching the permanent magnet due to the urging force of the valve spring, the valve spring expands, the set force (set force) decreases, and the magnet attracts. As a result, the force increases, and the overall valve-holding holding force (spring + magnet) increases.

  As a result, the amount of input energy necessary to achieve the target lift amount also increases, and the target lift amount is not reached in the drive pulse application period determined by the above-described method, and the valve does not reach the control target. There is a problem that the degree of valve opening and the valve opening timing cannot be secured, and the combustion state and fuel consumption in the cylinder deteriorate.

  As an example, in FIG. 6, when the cotter and the valve spring receiver are close to the 0.5 mm magnet, the force of the magnet applied to the valve opening, the force of the spring, etc. The comparison of the sum of and the amount of energy required for valve opening is shown. FIG. 7 shows the calculation results of the valve lift profile when the drive pulse application period is the same. From FIG. 7, when the cotter and the valve spring receiver are close to the 0.5 mm magnet, the lift amount of the valve opening is expected to be slightly lower than the lift amount of A in the initial setting. Is done.

JP 2003-328713 A JP 2006-152872 A JP 2011-196233 A

  The present invention has been made in view of the above, and an object of the present invention is to detect wear over time of a cotter that fixes a valve spring receiver from the behavior of an intake / exhaust valve during vehicle travel, and It is an object of the present invention to provide a variable valve system, an internal combustion engine, and a control method for the variable valve system that can prevent the intake / exhaust valve from dropping into the valve.

To achieve the above object, a variable valve system according to the present invention includes an urging means for urging a valve constituting an intake valve or an exhaust valve of an internal combustion engine in a valve closing direction by a valve spring and a magnet, and the urging means. An urging means receiver for receiving the urging force, a cotter for fixing the urging means receiver to the valve, a valve opening means for driving the valve in a valve-opening direction in a camless manner , and the valve opening means In a variable valve system comprising a control device that controls opening and closing of a valve, the variable valve system includes gap detection means including a gap sensor that detects an actual valve lift amount of the valve, and the control device detects the gap sensor. The actual valve lift amount is compared with the target lift amount which is a target value in the opening / closing control, and the actual valve lift amount is compared with the target lift amount. Configured with a cotter wear detection means for detecting the wear of the cotter is smaller.

  According to this configuration, the wear of the cotter over time can be detected from the behavior of the intake and exhaust valves during vehicle running (motoring), and the intake and exhaust valves can be prevented from falling into the combustion chamber. It becomes.

In the variable valve system described above, the gap detecting means detects the actual valve lift amount a plurality of times during one valve opening period over a plurality of cycles, and detects the cotter wear. A cycle in which the means calculates a plurality of differences between the target lift amount and the actual valve lift amount within one valve opening period of the valve, and a statistical value calculated from the calculated plurality of differences exceeds a preset first threshold value A warning signal is generated when the number of times is continuously generated for a predetermined first time or more, and the number of cycles that is greater than the first threshold and exceeds a preset second threshold If it is configured to generate a notification signal that the wear of the cotter has been detected when it occurs continuously for the set second set number of times or more, the following effects can be obtained.

  In other words, it is possible to avoid falling of the valve into the combustion chamber by detecting when the actual lift amount is lower than the target lift amount as a means for detecting wear over time of the cotter from the calculation result. However, in an actual engine, a variation of about ± 1 mm with respect to the target lift amount is expected due to a variation in the fuel injection amount and the intake / exhaust pressure cycle. Therefore, as detection of wear over time of the cotter, a warning is given when a cycle in which the statistical value of the difference between the target lift amount and the actual lift amount exceeds the first threshold occurs multiple times, that is, continuously for the first set number of times ( When the cycle exceeding the second threshold value occurs a plurality of times, that is, continuously for the second set number of times, the wear is detected.

  As a result, if there is an opportunity for repair from the warning signal, information that it is better to replace the cotter with a new one can be obtained, and information that repair should be performed can be obtained from the notification signal. Thus, it becomes possible to deal with the problem more precisely, and it becomes easier to prevent the intake and exhaust valves from dropping into the combustion chamber.

  Here, as a statistical value of the difference between the target lift amount and the actual valve lift amount in the valve opening period, the maximum value, the average value, the standard deviation in the time series of the difference in the valve opening period, and A time series maximum value, average value, minimum value, standard deviation, etc. of the difference in a preset detection period shorter than the valve opening period can be used. The number of cycles is the number of times that the piston stroke that opens the valve is counted as one time.

  The first threshold value is, for example, a value of 0.5 mm or more and 1.5 mm or less, preferably 1.0 mm, and the second threshold value is, for example, a value of 0.5 mm or more and 1.5 mm or less, preferably 1. Although it is 0 mm, it may be a value equal to the first threshold value. In addition, the first set number of times is, for example, a value of 5 to 15 times, preferably 10 times, and the second set number of times is, for example, a value of 15 to 25 times, preferably 20 times. It is preferable.

  And the internal combustion engine of this invention for achieving said objective is comprised including said variable valve system, and there can exist an effect similar to said variable valve system.

And the control method of the variable valve system of the present invention for achieving the above object comprises an urging means for urging a valve forming an intake valve or an exhaust valve of an internal combustion engine in a valve closing direction by a valve spring and a magnet. A biasing means receiver that receives a biasing force of the biasing means; a cotter that fixes the biasing means receiver to the valve; a valve opening means that drives the valve in a valveless direction in a camless manner ; and the valve In a control method of a variable valve system including a control device that performs opening / closing control of the valve by valve opening means, an actual valve lift amount of the valve is detected by a gap sensor, and the gap sensor is detected by the control device. The detected actual valve lift amount is compared with the target lift amount which is the target value in the opening / closing control, and the actual valve lift amount is compared with the target lift amount. A method characterized by detecting the wear of the cotter when again.

Further, in the above control method of the variable valve system , an actual valve lift amount is detected by the gap sensor a plurality of times during one valve opening period of the valve over a plurality of cycles. The controller calculates a plurality of differences between the target lift amount and the actual valve lift amount within one valve opening period of the valve , and then calculates a statistical value within the valve opening period of the valve from the calculated plurality of differences. And then generating a warning signal when the number of cycles in which the calculated statistical value exceeds a preset first threshold value continuously occurs for a preset first set number of times or more, and A notification that the wear of the cotter has been detected when the number of cycles that is greater than the first threshold and exceeds the preset second threshold occurs continuously for the preset second preset number of times or more. The occur.

  According to these control methods for the variable valve system, the same effects as the above variable valve system can be obtained.

  According to the variable valve system, the internal combustion engine, and the control method of the variable valve system of the present invention, it is possible to detect the wear of the cotter over time from the behavior of the intake and exhaust valves when the vehicle travels, and to the combustion chamber It is possible to prevent the intake / exhaust valve from dropping.

It is a figure showing typically composition of a variable valve system of an embodiment concerning the present invention. It is a figure which shows each means in the variable valve system of embodiment which concerns on this invention. It is a figure which shows the time series of target lift amount and actual valve lift amount. It is a figure which shows the valve lift amount with respect to the crank angle of the intake / exhaust valve by hydraulic drive and cam drive. It is a figure which shows the valve speed at the time of valve closing of the exhaust valve by hydraulic pressure and cam drive. It is a figure which shows the energy requested | required for valve opening of the magnetic force with respect to valve lift amount, a spring force, its sum, and an intake / exhaust valve. It is a figure which shows the time series of the valve lift amount before the movement of a cotter and a valve spring holder, and after a change.

  A variable valve system, an internal combustion engine, and a variable valve system control method according to embodiments of the present invention will be described. In the following description, a valve spring and a magnet are used together to urge the valve in the valve closing direction, but only the valve spring may be used.

  As shown in FIGS. 1 and 2, the variable valve system 1 includes a valve 4 that forms an intake valve or an exhaust valve of an internal combustion engine, a valve spring 8 that biases the valve 4 in a valve closing direction, and a magnet (illustrated). A valve opening / closing means S2 having a hydraulic control chamber 18 for applying fluid pressure to the valve 4, and supplying a working fluid to the hydraulic control chamber 18 to open the valve 4 A fluid supply means S3 having a hydraulic pump 11 and a first operating valve 15a for operating the valve, and a second operation for releasing the fluid pressure in the hydraulic control chamber 18 and closing the valve 4 by the biasing means S1. This is a system that includes a pressure release means S4 having a valve 15b and a control device 12 that controls opening and closing of the valve 4, and drives the valve 4 by the fluid pressure of the working fluid.

  More specifically, as shown in FIG. 1, the valve 4 is provided on the cylinder head 20 of the engine so as to be movable up and down. The valve shaft 4b of the valve 4 is formed in a shaft shape as a whole, an umbrella-shaped valve body 4a is provided at a lower end portion thereof, a hydraulic piston 4c is provided at an upper end portion thereof, and a valve spring receiver is provided at an intermediate portion in the longitudinal direction. (Human part) 4d is provided. The valve body 4a is configured to be separated from the valve seat portion (seat portion) 6 of the cylinder head 20 when the valve is opened, and to be seated on the valve seat portion 6 when the valve is closed.

  A valve spring 8 that biases the valve 4 in the valve closing direction is disposed in a compressed state between the valve spring receiver 4d of the valve 4 and the cylinder head 20, and the valve spring receiver 4d is disposed in the cylinder head 20. A magnet (not shown) is provided to attract the valve 4 upward and bias the valve 4 in the valve closing direction. These valve springs 8 and magnets constitute urging means S1 for urging the valve 4 in the valve closing direction. The force for urging the valve 4 in the valve closing direction is increased to increase the valve closing speed of the valve 4. The controllability of the valve 4 is improved.

  Further, a hydraulic control chamber (pressure chamber) 18 facing the upper surface of the hydraulic piston 4c is provided in the cylinder head 20, and the bottom surface thereof is closed by the upper surface of the hydraulic piston 4c. The hydraulic control chamber 18 is supplied with hydraulic oil (working fluid) for lifting the valve 4 in the valve opening direction. Light oil common to engine fuel is used as the hydraulic oil for opening the valve 4.

  Further, on the side of the hydraulic control chamber 18, a first operating valve (first actuator) 15a for switching between supply and stop of supply of high-pressure hydraulic oil to the hydraulic control chamber 18 is provided. By the operation of the first operation valve 15a, hydraulic oil composed of high-pressure fuel is supplied to the hydraulic control chamber 18 from the hydraulic pump 11 (or common rail) through the hydraulic line 21 via the flow path A. The hydraulic pump 11 is driven by receiving driving force from the engine via gears 13a and 13b whose rotational speeds are monitored by rotational speed sensors 14a and 14b.

  Further, a second operating valve (second actuator) 15 b is provided above the hydraulic control chamber 18 so as to block the upper surface of the hydraulic control chamber 18. By the operation of the second operation valve 15b, the hydraulic oil in the hydraulic control chamber 18 returns to the hydraulic pump 11 through the hydraulic line 21 via the flow path B.

  The first operating valve 15a and the second operating valve 15b are controlled by a control signal from the control device 12 by an electromagnetic solenoid or the like. That is, the hydraulically driven variable valve system 1 receives a command from an engine control unit (ECU) 2 called an engine control unit and sends a control signal from the control unit 12 of the variable valve system 1 to a signal line 3. The hydraulic pump 11 is driven to drive the hydraulic pump 11, and the high-pressure hydraulic oil boosted by the hydraulic pump 11 is supplied to the hydraulic control chamber 18 through the flow path A of the hydraulic pipe 21. High pressure hydraulic oil is returned from the hydraulic control chamber 18 to the hydraulic pump 11 through the flow path B of the hydraulic pipe 21.

  More specifically, when the valve body 4a of the valve 4 is opened, the hydraulic pump 11 operates the first operating valve 15a by the control signal from the control device 12 to open the valve body 4a of the valve 4. By sending the pressurized high-pressure hydraulic oil to the hydraulic control chamber 18 through the flow path A, the hydraulic piston 4c is pushed down against the urging force of the valve spring 8 and the magnet by the hydraulic pressure of the hydraulic control chamber 18, and the cylinder head 20 The valve is opened away from the valve seat 6.

  Further, when the valve is closed, the second operating valve 15 b is operated by a control signal from the control device 12, and high pressure hydraulic oil is released from the hydraulic control chamber 18 to the hydraulic pump 11 through the flow path B of the hydraulic pipe 21. The hydraulic pressure in the control chamber 18 is lowered, the hydraulic piston 4c is pushed up by the biasing force of the valve spring 8 and the magnet, and the valve body 4a is brought into contact with the valve seat portion 6 of the cylinder head 20 to close the valve.

  When the valve 4 is opened in the hydraulically driven variable valve system 1, the amount of high-pressure hydraulic oil supplied to the hydraulic control chamber 18 differs depending on the operating state of the engine. A required energy amount E is calculated according to Lt, and an instruction pulse of a period extracted from the map for the required energy amount E and the hydraulic oil pressure is sent to the first operating valve 15a and the second operating valve 15b to control them. doing.

  In calculating the required energy amount E, the cylinder head 20 includes a cylinder sensor (not shown) for detecting the pressure in the cylinder and a supply / exhaust port sensor for detecting the pressure in the supply / exhaust port (not shown). (Not shown) and the differential pressure before and after the valve 4 when the valve is opened, that is, the pressure in the intake and exhaust ports and the pressure in the cylinder are measured, and the air system model provided in the control model and the cylinder pressure calculation A required energy amount E is calculated using the model.

  In this air system model, the engine speed, hydraulic oil input, supply / exhaust temperature, EGR valve opening and VGT (Variable Geometry Turbo) opening are used as parameters for the turbocharger specification and port shape. In the calculation model, the pressure before and after the valve at the valve opening timing of the supply / exhaust valve is calculated with respect to the engine specifications (displacement, geometric compression ratio, etc.) using the engine speed and the amount of hydraulic oil input as parameters. These parameters are obtained from the engine control device 2.

  Furthermore, in addition to the pressure calculation based on these control models, by adding the following mechanical physical formula, in the valve opening operation of the valve 4 in the variable valve system 1, an appropriate high-pressure hydraulic oil charging period and amount Ask for.

  That is, Fo is the force by which the high-pressure hydraulic oil pushes the valve 4, Fm is the suction force of the magnet, Fs is the reaction force of the valve spring 8, Fp is the force to the valve seat 6 from the intake / exhaust port side, and The force on the valve 4 is Fc. In this case, the force Fv applied to the valve 4 in the valve opening direction is expressed by the equation (1) of “Fv = Fo− (Fc−Fp) − (Fm + Fs)”.

Here, assuming that the pressure of the high-pressure hydraulic oil supplied to the hydraulic control chamber 18 is Po and the diameter of the upper surface of the valve facing the hydraulic control chamber 18 is φ1, Fo is “Fo = Po × (φ1 / 2) ² × π ”(2), and“ (Fc−Fp) ”on the right side of equation (1) uses the pressures Pc and Pp measured by the pressure sensor in the cylinder and at the intake and exhaust ports, and the seat of the valve 4 When the diameter is φ2, Equation (3) of “Fc−Fp = (Pc, Pp) × (φ2 / 2) ² × π” is obtained.

  However, since “(Pc, Pp)” fluctuates during the valve opening process, it is necessary to create a characteristic map by intake / exhaust system simulation such as “WAVE”. Further, regarding the pressure Pc at the time of opening the valve, the pressure Pc at the time of opening the valve is calculated considering the responsiveness of the pressure sensor and considering the change in the polytropy from the pressure immediately before the valve opening timing.

  For the Fm of “(Fm + Fs)” in the last term on the right side of the equation (1), the Fm characteristic map is created by investigating the attractive force of the magnet in advance. Is obtained by the equation (4) of “Fs = k × (L + Lb)” by measuring the spring constant k of the valve spring 8 and the length Lb at the time of attachment.

  By applying the above physical formula to the formula (1), the force Fv applied in the valve opening direction to the valve 4 with respect to the lift amount L in the valve opening process can be obtained. Thereby, the thrust W (J) necessary for opening the valve 4 to the set lift amount L is expressed by the equation (5) of “W = ∫FvdL” (integral range is 0 to L).

  The above physical formula is incorporated into the control logic, and first, the differential pressure before and after the valve at the opening and closing timing of the valve 4 is calculated from the engine specifications and the operating parameters. Next, the valve thrust W required for the set lift amount L is calculated, the required input amount Ow of the high-pressure hydraulic oil is calculated, and the required high-pressure hydraulic oil supply period Ta is determined from the characteristic map created in advance. . Thereby, the stable valve operation | movement in the variable valve system 1 is enabled by model base control.

  Therefore, since the differential pressure before and after the valve at the time of opening the valve is clarified and the valve thrust W required to obtain the lift amount L set at the time of opening and closing the valve is obtained and the required input amount Ow of the high pressure hydraulic oil is controlled, the valve 4 When the valve is opened, the valve thrust W required to obtain the set target lift amount Lt changes depending on the pressure before and after the valve 4, and is smaller or larger than the desired target lift amount Lt. Such a symptom can be prevented, and the influence on the fluctuation of the intake amount and the intake composition in the cylinder can be eliminated.

  In the above calculation, the valve spring 8 and the magnet (not shown) are used together to urge the valve 4 in the valve closing direction, but only the valve spring 8 may be used.

And in this invention, as shown in FIG. 1, it is provided with the gap detection means S5 which has the gap sensor 7 for detecting the actual valve lift amount Lm of the intake / exhaust valve 4. Further, the control device 12 compares the actual valve lift amount Lm detected by the gap sensor 7 with the target lift amount Lt, and is fitted into a groove provided near the upper end of the valve shaft 4b of the valve 4. The cotter wear detecting means for detecting the continuous wear of the cotter (valve stop ring) 5 for fixing the spring receiver 4d is provided. The cotter wear detecting means S6 detects the continuous wear of the cotter 5 based on the comparison between the actual valve lift amount Lm of the valve 4 and the target lift amount Lt.

  According to this configuration, it is possible to detect the wear of the cotter 5 over time from the behavior of the valve 4 during vehicle running (motoring), and to prevent the valve 4 from falling into the combustion chamber. Become.

  Then, the cotter wear detecting means S6 continues the cycle number Nm in which the statistical value ΔLv of the difference ΔL between the target lift amount Lt and the actual valve lift amount Lm within the valve opening period of the valve 4 exceeds the preset first threshold value ΔL1. When a predetermined first set number N1 or more is continuously generated, a warning signal is generated, and a cycle number Nn larger than the first threshold ΔL1 and exceeding a preset second threshold ΔL2 is generated. A notification signal indicating that the wear of the cotter 5 has been detected is generated when the occurrence occurs continuously for a second preset number of times N2 or more.

  Thus, if there is an opportunity for repair from the warning signal, information indicating that the cotter 5 should be replaced with a new one can be obtained, and information indicating that repair should be performed can be obtained from the notification signal. Therefore, it becomes easier to prevent the valve 4 from falling into the combustion chamber.

  Here, t is the elapsed time (or crank angle), and the statistical value of the difference ΔL (t) between the target lift amount Lt (t) and the actual valve lift amount Lm (t) in the valve opening period To of the valve 4 ΔLv includes the maximum value, average value, standard deviation in the time series of the difference ΔL (t) in the valve opening period To of the valve 4, and the difference in the preset detection period Tc shorter than the valve opening period To of the valve 4. A time series maximum value, average value, minimum value, standard deviation, etc. of ΔL (t) can be used. The number of cycles N is the number of times that the time when the piston 4 enters the piston stroke where the valve 4 opens is counted as one time.

  The first threshold value ΔL1 is, for example, a value of 0.5 mm or more and 1.5 mm or less, preferably 1.0 mm, and the second threshold value ΔL2 is, for example, a value of 0.5 mm or more and 1.5 mm or less, preferably Although it is 1.0 mm, it may be a value equal to the first threshold value ΔL1. Further, the first set number N1 is, for example, a value of 5 to 15 times, preferably 10 times, and the second set number N2 is, for example, a value of 15 to 25 times, preferably 20 times. It is preferable that

  The internal combustion engine of the embodiment according to the present invention is configured to include this variable valve system 1.

  According to the variable valve system 1, the internal combustion engine, and the control method for the variable valve system configured as described above, the wear of the cotter 5 over time can be detected from the behavior of the intake and exhaust valves when the vehicle is running, It is possible to prevent the valve 4 of the intake / exhaust valve from falling into the chamber.

1 Variable Valve System 2 Engine Control Unit (ECU)
3 Signal line 4 Valve (intake valve or exhaust valve)
4a Valve body 4b Valve shaft 4c Hydraulic piston 4d Valve spring holder (buttock)
5 Cotta 6 Valve seat (seat)
7 Gap sensor 8 Valve spring 11 Hydraulic pump 12 Control devices 13a, 13b Gears 14a, 14b Rotational speed sensor 15a First operating valve (first actuator)
15b Second actuation valve (second actuator)
18 Hydraulic control chamber (pressure chamber)
20 Cylinder head 21 Hydraulic pipe S1 Energizing means S2 Valve opening / closing means S3 Fluid supply means S4 Pressure release means S5 Gap detection means S6 Cotta wear detection means

Claims (5)

An urging means for urging a valve constituting an intake valve or an exhaust valve of an internal combustion engine in a valve closing direction by a valve spring and a magnet , an urging means receiver for receiving an urging force of the urging means, and the urging means receiver In a variable valve system comprising: a cotter that is fixed to the valve; a valve opening means that drives the valve in a valve opening direction in a camless manner ; and a control device that controls the opening and closing of the valve by the valve opening means.
A gap detecting means comprising a gap sensor for detecting an actual valve lift amount of the valve;
When the control device compares the actual valve lift amount detected by the gap sensor with the target lift amount that is the target value in the opening / closing control, and the actual valve lift amount is smaller than the target lift amount. A variable valve system comprising cotter wear detecting means for detecting wear of the cotter. Over a plurality of cycles, the gap detection means detects the actual valve lift amount a plurality of times for one valve opening period of the valve,
The cotter wear detecting means calculates a plurality of differences between the target lift amount and the actual valve lift amount within a single valve opening period of the valve, and a statistical value calculated from the calculated plurality of differences is a preset first value. A warning signal is generated when the number of cycles exceeding the threshold value is continuously generated for a predetermined first set number of times or more, and further exceeds a preset second threshold value that is greater than the first threshold value. The variable valve system according to claim 1, wherein a notification signal indicating that the wear of the cotter has been detected is generated when the number of cycles is continuously generated for a predetermined second set number or more.   An internal combustion engine comprising the variable valve system according to claim 1. An urging means for urging a valve constituting an intake valve or an exhaust valve of an internal combustion engine in a valve closing direction by a valve spring and a magnet , an urging means receiver for receiving an urging force of the urging means, and the urging means receiver Control of a variable valve system comprising: a cotter fixed to the valve; a valve opening means for driving the valve in a valve- opening direction in a camless manner ; and a control device for controlling the opening and closing of the valve by the valve opening means. In the method
The gap sensor detects the actual valve lift amount of the valve,
When the actual valve lift amount is smaller than the target lift amount by comparing the actual valve lift amount detected by the gap sensor with the target lift amount that is the target value in the opening / closing control from the control device. A control method for a variable valve system, wherein wear of the cotter is detected. Over a plurality of cycles, the gap sensor detects the actual valve lift amount a plurality of times for one valve opening period of the valve,
The controller calculates a plurality of differences between the target lift amount and the actual valve lift amount within one valve opening period of the valve, and then calculates a statistical value within the valve opening period of the valve from the calculated plurality of differences. And then generating a warning signal when the number of cycles in which the calculated statistical value exceeds a preset first threshold value continuously occurs for a preset first set number of times or more, and A notification signal indicating that the wear of the cotter has been detected is generated when the number of cycles that is greater than the first threshold and exceeds the preset second threshold occurs continuously for the preset second preset number of times or more. The control method of the variable valve system of Claim 4.

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