JP2009047200A - Engine natural frequency detection method, and active vibration isolation support device control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable detection of a roll resonance frequency of an engine, while suppressing vibration due to roll resonance of the engine by controlling an active vibration isolation support device using the roll resonance frequency. <P>SOLUTION: The natural vibration frequency of the roll resonance which does not occur since the engine rotation number is high in a normal operation range of the engine is detected at the time of engine start or stop when the engine rotation number is lower than the normal operation range, and thus the natural vibration frequency of the roll resonance can be detected with a good accuracy. A current is generated by electromotive force of an actuator of the active vibration isolation support device excited by the engine immediately before stopping its rotation, and the frequency of the current is used to detect the natural vibration frequency of the engine, and the roll resonance of the engine is suppressed by controlling the operation of the active vibration frequency isolation support device at the time of engine start from the natural vibration frequency, thereby not only eliminating the need of a specific frequency detection sensor, but also effectively reducing the vibration at the time of engine start when the roll resonance becomes strong. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine natural frequency detection method for detecting a natural frequency of a rigid resonance of an engine supported on a vehicle body via an active vibration isolation support device, and an active vibration isolation using the natural frequency detection method. The present invention relates to a method for controlling a support device.

The crank angular speed is calculated from the time interval of the crank pulse output at each predetermined rotation angle of the crankshaft, the crankshaft torque is calculated from the crank angular acceleration obtained by time differentiation of the crank angular speed, and the engine vibration state Patent Document 1 below discloses an active vibration isolating support device that estimates the above and controls the energization of a coil of an actuator in accordance with the vibration state of the engine to exert a vibration isolating function.
JP 2005-3156 A

  By the way, since the torque of the engine fluctuates according to the phase of the crankshaft, as a reaction, the roll moment for rolling the engine body around the crankshaft also fluctuates according to the phase of the crankshaft. Since the period at which this roll moment increases or decreases changes according to the engine speed, when the period at which the roll moment increases or decreases at a specific engine speed matches the roll resonance frequency of the engine elastically mounted on the vehicle body, There is a problem that vehicle vibration that is uncomfortable for passengers occurs. Therefore, it is necessary to detect the roll resonance frequency and operate the active vibration isolating support device in the engine speed region where the roll resonance occurs to suppress the vibration associated with the roll resonance.

  However, in general, the roll resonance frequency is lower than the vibration frequency at the rotation speed in the normal operation region of the engine (rotation speed equal to or higher than the idling rotation speed). Therefore, the roll resonance frequency is set during normal operation of the engine. There was a problem that it could not be detected.

  The present invention has been made in view of the above-described circumstances, and makes it possible to detect the rigid resonance frequency of the engine, and to control the active vibration isolating support device using the rigid resonance frequency to thereby detect the rigid resonance of the engine. The purpose is to suppress vibration.

  In order to achieve the above object, according to the first aspect of the present invention, the natural frequency detection of the engine for detecting the natural frequency of the rigid resonance of the engine supported on the vehicle body via the active vibration isolating support device. In the method, a method for detecting the natural frequency of the engine is proposed, wherein the natural frequency is detected when the engine is started or stopped.

  According to the invention described in claim 2, in addition to the structure of claim 1, the current is generated by the electromotive force of the actuator of the active vibration isolating support device that is vibrated by the engine at the time of starting or stopping. And a method of detecting the natural frequency of the engine, wherein the natural frequency is detected from the frequency of the current.

  According to a third aspect of the present invention, there is provided a method of controlling an active vibration isolating support device used in the method of the first or second aspect, wherein the engine is started or stopped when the engine is started or stopped. A control method for an active vibration isolating support device is proposed in which the operation of the active vibration isolating support device is controlled based on the natural frequency to suppress rigid resonance of the engine.

  According to the invention described in claim 4, in addition to the configuration of claim 3, the operation of the active vibration isolating support device when the engine is started based on the natural frequency detected when the engine is stopped. A control method for an active vibration isolating support device is proposed in which the rigid resonance of the engine is suppressed by controlling the vibration.

  According to the first aspect of the present invention, the natural frequency of the rigid body resonance that does not occur because the engine speed is high in the normal operation range of the engine is reduced at the time of starting or stopping when the engine speed is lower than that in the normal operation range. Since it is sometimes detected, the natural frequency of the rigid body resonance can be detected with high accuracy.

  According to the second aspect of the present invention, a current is generated by the electromotive force of the actuator of the active vibration isolating support device that is vibrated by the engine when the engine is started or stopped, and the natural frequency of the engine is determined from the frequency of the current. Therefore, a special frequency detection sensor is not necessary.

  According to the third aspect of the present invention, when the engine is started or stopped, the operation of the active vibration isolating support device is controlled based on the natural frequency to suppress the rigid resonance of the engine. Thus, the vibration can be effectively reduced by fully exhibiting the function of the active vibration isolating support device at the start or stop when the vibration becomes strong.

  According to the fourth aspect of the present invention, the rigid vibration of the engine is suppressed by controlling the operation of the active vibration isolating support device when starting the engine based on the natural frequency detected when the engine is stopped. The engine is supported by an active anti-vibration support device at start-up when the resonance of the rigid body of the engine is stronger or at start-up when the driver is sensitive to vibrations because the driver pays attention to the rotational state of the engine (whether or not it has started). Can be effectively reduced. In addition, since the operation of the active vibration isolating support device is controlled based on the latest one of the natural frequencies detected periodically, the vibration isolation of the active vibration isolating support device is based on the natural frequency with high accuracy. The effect can be exhibited effectively.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 9 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an active vibration isolating support device, FIG. 2 is an enlarged view of part 2 of FIG. 1, and FIG. 3 is an active vibration isolating support. FIG. 4 is a flowchart showing the control method of the actuator during normal operation, FIG. 5 is an explanatory diagram of step S5 of the flowchart of FIG. 4, and FIG. 6 is a flowchart showing the operation when the engine is stopped. 7 is a flowchart for explaining the operation at the time of starting the engine, FIG. 8 is a view showing the waveform of the roll vibration of the engine, and FIG. 9 is a view showing the waveform of the roll vibration and the current waveform when the engine is stopped.

  As shown in FIGS. 1 and 2, an active anti-vibration support device M (active control mount) used for elastically supporting an automobile engine on a body frame is substantially axisymmetric with respect to an axis L. A substantially cup-shaped actuator case having an open upper surface between a flange portion 11a at the lower end of the substantially cylindrical upper housing 11 and a flange portion 12a at the upper end of the generally cylindrical lower housing 12. The outer peripheral flange portion 13a, the outer peripheral portion of the annular first elastic body support ring 14, and the outer peripheral portion of the annular second elastic body support ring 15 are overlapped and joined by caulking. At this time, the annular first floating rubber 16 is interposed between the flange portion 12a of the lower housing 12 and the flange portion 13a of the actuator case 13, and the upper portion of the actuator case 13 and the inner surface of the second elastic body support ring 15 By interposing the annular second floating rubber 17 therebetween, the actuator case 13 is floatingly supported so as to be movable relative to the upper housing 11 and the lower housing 12.

  The lower end and the upper end of the first elastic body 19 formed of thick rubber are joined to the first elastic body support ring 14 and the first elastic body support boss 18 disposed on the axis L by vulcanization adhesion. Is done. A diaphragm support boss 20 is fixed to the upper surface of the first elastic body support boss 18 with bolts 21, and the outer peripheral portion of the diaphragm 22, which is joined to the diaphragm support boss 20 by vulcanization adhesion, is added to the upper housing 11. Joined by sulfur adhesion. An engine mounting portion 20a integrally formed on the upper surface of the diaphragm support boss 20 is fixed to an engine (not shown). In addition, the vehicle body attachment portion 12b at the lower end of the lower housing 12 is fixed to a vehicle body frame (not shown).

  A flange portion 23a at the lower end of the stopper member 23 is coupled to the flange portion 11b at the upper end of the upper housing 11 by bolts 24 ... and nuts 25 ..., and a diaphragm support boss 20 is attached to a stopper rubber 26 attached to the upper inner surface of the stopper member 23. The engine mounting portion 20a that protrudes from the upper surface of the upper and lower surfaces faces each other so as to be capable of contacting. When a large load is input to the active vibration isolating support device M, the engine mounting portion 20a abuts against the stopper rubber 26, thereby suppressing excessive displacement of the engine.

  The outer peripheral portion of the second elastic body 27 formed of a film-like rubber is joined to the second elastic body support ring 15 by vulcanization adhesion, and the movable member 28 is added so as to be embedded in the central portion of the second elastic body 27. Joined by sulfur adhesion. The outer peripheral part of the second elastic body 27 is sandwiched between the second elastic body support ring 15 and a yoke 44 described later, and the annular thick part at the tip thereof exhibits a sealing function. A disk-shaped partition wall member 29 is fixed between the upper surface of the second elastic body support ring 15 and the outer periphery of the first elastic body 19, and the first partition partitioned by the partition wall member 29 and the first elastic body 19. The liquid chamber 30 and the second liquid chamber 31 partitioned by the partition member 29 and the second elastic body 27 communicate with each other through a communication hole 29 a formed at the center of the partition member 29.

  An annular communication path 32 is formed between the first elastic body support ring 14 and the upper housing 11, and one end of the communication path 32 communicates with the first liquid chamber 30 through the communication hole 33. The other end communicates with the third liquid chamber 35 defined by the first elastic body 19 and the diaphragm 22 through the communication hole 34.

  Next, the structure of the actuator 41 that drives the movable member 28 will be described.

  The fixed core 42, the coil assembly 43, and the yoke 44 are sequentially attached to the inside of the actuator case 13 from the bottom to the top. The coil assembly 43 includes a coil 46 disposed between the fixed core 42 and the yoke 44, and a coil cover 47 that covers the outer periphery of the coil 46. The coil cover 47 is integrally formed with a connector 48 that extends through the openings 13b and 12c formed in the actuator case 13 and the lower housing 12 and extends to the outside.

  A seal member 49 is disposed between the upper surface of the coil cover 47 and the lower surface of the yoke 44, and a seal member 50 is disposed between the lower surface of the coil 46 and the upper surface of the fixed core 42. These seal members 49 and 50 can prevent water and dust from entering the internal space of the actuator 41 from the openings 13 b and 12 c formed in the actuator case 13 and the lower housing 12.

  A thin cylindrical bearing member 51 is fitted to the inner peripheral surface of the cylindrical portion 44a of the yoke 44 so as to be vertically slidable. An upper flange 51a bent radially inward is formed at the upper end of the bearing member 51. A lower flange 51b that is bent radially outward is formed at the lower end. A set spring 52 is disposed in a compressed state between the lower flange 51b and the lower end of the cylindrical portion 44a of the yoke 44. The elastic force of the set spring 52 causes the lower flange 51b to be fixed to the fixed core 42 via the elastic body 53. The bearing member 51 is supported by the yoke 44 by being pressed against the upper surface of the yoke 44.

  A substantially cylindrical movable core 54 is fitted to the inner peripheral surface of the bearing member 51 so as to be slidable up and down. A rod 55 extending downward from the center of the movable member 28 penetrates the center of the movable core 54 loosely, and a nut 56 is fastened to the lower end thereof. A set spring 58 in a compressed state is disposed between a spring seat 57 provided on the upper surface of the movable core 54 and the lower surface of the movable member 28, and the movable core 54 is pressed against the nut 56 by the elastic force of the set spring 58. Fixed. In this state, the lower surface of the movable core 54 and the upper surface of the fixed core 42 face each other via the conical air gap g. The nut 56 is fastened to the rod 55 with its vertical position adjusted in an opening 42 a formed at the center of the fixed core 42, and the opening 42 a is closed with a rubber cap 60.

  The active vibration isolating support device M configured as described above is controlled by the electronic control unit U according to the vibration state of the engine.

  The electronic control unit U includes a crank pulse sensor Sa that detects a crank pulse that is output 24 times per rotation of the crankshaft, that is, once every 15 ° of the crank angle, as the crankshaft of the engine rotates. The cam angle sensor Sb is output three times per one rotation of the shaft, that is, once every top dead center of each cylinder. The electronic control unit U estimates the vibration state of the engine based on the outputs of the crank pulse sensor Sa and the cam angle sensor Sb, and controls energization to the actuator 41 of the active vibration-proof support device M.

  The coil 46 of the actuator 41 is excited by energization control from the electronic control unit U, attracts the movable core 54, and moves the movable member 28 downward. As the movable member 28 moves, the second elastic body 27 defining the second liquid chamber 31 is deformed downward, and the volume of the second liquid chamber 27 increases. Conversely, when the coil 46 is demagnetized, the second elastic body 27 is deformed upward by its own elasticity, the movable member 28 and the movable core 54 are raised, and the volume of the second liquid chamber 31 is reduced.

  Thus, when low-frequency engine shake vibration is generated while the vehicle is running, the first elastic body 19 is deformed by the load input from the engine and the volume of the first liquid chamber 30 is changed. The liquid goes back and forth between the first liquid chamber 30 and the third liquid chamber 35 that are connected to each other. When the volume of the first liquid chamber 30 is enlarged / reduced, the volume of the third liquid chamber 25 is reduced / expanded accordingly, but the volume change of the third liquid chamber 35 is absorbed by the elastic deformation of the diaphragm 22. At this time, the shape and size of the communication path 32 and the spring constant of the first elastic body 19 are set so as to exhibit a low spring constant and a high damping force in the frequency region of the engine shake vibration. The vibration transmitted to can be effectively reduced.

  In the frequency region of the engine shake vibration, the actuator 41 is kept in an inoperative state.

  Vibration at a higher frequency than the engine shake vibration, that is, vibration during idling due to rotation of the crankshaft of the engine or vibration during cylinder deactivation operation in which a part of the cylinder of the engine is deactivated to drive the engine occurred. In this case, since the liquid in the communication path 32 connecting the first liquid chamber 30 and the third liquid chamber 35 is in a stick state and cannot exhibit the anti-vibration function, the actuator 41 is driven to exhibit the anti-vibration function.

  The electronic control unit U is based on signals from the crank pulse sensor Sa, the cam angle sensor Sb, the engine speed sensor Sc, and the engine ECU 10 in order to operate the actuator 41 of the active vibration isolation support device M to exhibit the vibration isolation function. The energization to the coil 46 is controlled.

  As shown in FIG. 3, the V-type engine E includes a front bank Bf and a rear bank Br, and the front side and the rear side thereof are supported by the active type vibration isolation support devices M and M, respectively. The electronic control unit U receives signals from the crank pulse sensor Sa and the engine control ECU 10 in order to actuate the actuators 41, 41 of the active vibration isolation support devices M, M on the front side and the rear side to exhibit the vibration isolation function. The energization to the actuators 41 is controlled based on the above.

  Next, control of the active vibration isolating support apparatus M having the above configuration will be described. The engine E is supported on the front bank Bf side and the rear bank Br side by active vibration isolation support devices M and M, respectively, and both the active vibration isolation support devices M and M are controlled independently.

  First, based on the flowchart of FIG. 4, control in a normal operation state except when the engine E is started will be described.

  Based on information from the engine ECU 10, it is determined in advance whether the cylinder is in a cylinder deactivation operation state in which some of the cylinders of the engine are deactivated or in an all cylinder operation state in which all cylinders of the engine are operated. This embodiment will be described as a 4-cycle V-type 6-cylinder engine. During all cylinder operation, six explosions occur during two revolutions of the crankshaft, so the crank angle of the vibration cycle is 120 °. In this vibration cycle, 8 crank pulses are output every 15 ° of the crank angle. In addition, during the cylinder deactivation operation in which the operation of the cylinder in one bank is deactivated, three explosions occur during two rotations of the crankshaft, so the crank angle of the vibration period is 240 °, and 16 crank pulses are produced during that time. Is output.

  For example, when it is determined that the engine is in the all-cylinder operation state, first, in step S1, a crank angle with respect to the vibration period T of the engine (in this case, 120 °) is determined. In subsequent step S2, eight crank pulses in the vibration period T are read, and the time interval of the crank pulses is calculated. As shown in FIG. 5, eight crank pulses are output during the vibration period T, and their time intervals tn (t1, t2, t3,..., T8) vary according to the variation of the angular speed of the crankshaft. .

  That is, in the engine explosion stroke, the crank angular speed ω is increased and the time interval tn is shortened, and in the engine compression stroke, the crank angular velocity ω is decreased and the time interval tn is increased, but in addition, the engine speed Ne is increased. In the process, the time interval tn becomes shorter due to the increase in the crank angular speed ω, and in the process where the engine speed Ne decreases, the time interval tn becomes longer due to the decrease in the crank angular speed ω. Therefore, the time interval tn of the crank pulse shown in FIG. 5 depends on factors caused by the fluctuation of the crank angular speed ω accompanying the vibration within each vibration period T of the engine and the fluctuation of the crank angular speed ω accompanying the increase / decrease of the engine speed Ne. It includes the element that originates.

  Of the two elements described above, the former element (the fluctuation of the crank angular velocity ω accompanying the vibration) affects the control of the active vibration isolating support apparatus M, and affects the control of the active vibration isolation support apparatus M. It is necessary to eliminate the latter element (the fluctuation of the crank angular speed ω accompanying the increase or decrease of the engine speed Ne) that is not given.

  In the subsequent step S3, an accumulated time Σtn = t1 + t2 + t3 +... + T8 of eight time intervals tn of crank pulses is calculated. This accumulated time Σtn corresponds to the vibration period T.

  In subsequent step S4, an average accumulated time of eight time intervals tn is calculated. As is apparent from FIG. 5, the cumulative time line is curved in an S shape, but the average cumulative time line is a straight line connecting the start point and the end point of the cumulative time line. That is, the average accumulated time corresponds to the accumulated time when the crank angular velocity ω is constant, and the value increases by T / 8 every time the crank angle increases by 15 °.

  In the subsequent step S5, eight deviations Δt1, Δt2, Δt3,..., Δt8 are calculated by subtracting the average cumulative time from the cumulative time at each position of the crank angle every 15 °. The lower S-shaped curve line in FIG. 5 represents the deviation Δtn. This line shows the fluctuation waveform of the time interval tn of the crank pulse excluding the influence of the fluctuation of the engine speed Ne, that is, the crank angular speed ω. This corresponds to a shift of the crank pulse with respect to the time interval tn in the case of being constant.

  Assuming that there is no engine vibration, if the engine speed Ne is constant, the accumulated time of the time interval tn increases linearly in the same way as the average accumulated time, but when the engine speed Ne increases or decreases. Therefore, the accumulated time of the time interval tn deviates from the linear average accumulated time. However, in the present embodiment, the fluctuation of the engine speed Ne is calculated by calculating the deviation Δtn from the average accumulated time based on a linear average accumulated time obtained by averaging the actually varying engine speed Ne. Thus, the deviation Δtn caused only by the vibration of the engine can be obtained. This is nothing but finding the deviation of the actual angular velocity from the average angular velocity of the crankshaft.

  In the next step S6, the maximum value and the minimum value of the deviation Δtn are determined, and the crank speed variation VAPP is calculated based on the deviation between the maximum value and the minimum value. In step S7, the output timing of the cam angle sensor Sb is calculated. The phase of vibration is estimated based on the time n to the minimum value. In step S8, the amplitude of vibration is calculated based on the map of the fluctuation amount VAPP stored in advance in the electronic control unit U and the engine speed, and the current waveform applied to the actuator 41 is determined. Based on this map, the output timing of the current waveform applied to the actuator 41 is determined.

  When it is determined that the engine is in a cylinder deactivation operation state, 16 crank pulses in the vibration period T are read, and a current waveform applied to the actuator 41 and its output timing in the same procedure as in the all cylinder operation state. And decide.

  As described above, when the engine vibrates, the vibration of the engine is transmitted to the vehicle body frame by expanding and contracting the active vibration isolating support device M so as to follow the vertical movement of the engine according to the amplitude and phase of the vibration. The vibration-proof function can be exhibited by suppressing the occurrence of the vibration.

  By the way, the engine E converts the force by which the explosion of the air-fuel mixture in the combustion chamber pushes down the piston into the rotational motion of the crankshaft through the connecting rod. A roll moment will act. Since the frequency at which the roll moment fluctuates changes according to the engine speed, when the frequency at which the roll moment fluctuates at a specific engine speed matches the roll resonance frequency of the engine E, vehicle vibration that is uncomfortable for the passengers occurs. To do.

  In general, since the roll resonance frequency is lower than the vibration frequency at the rotation speed (rotation speed equal to or higher than the idling rotation speed) in the normal operation region of the engine E, the engine rotation speed is idling when the engine E is started and stopped. Roll resonance of the engine E occurs when a predetermined rotational speed lower than the rotational speed is reached.

  Therefore, in the present embodiment, the roll resonance frequency of the engine E is detected by detecting the roll resonance frequency of the engine E and operating the active vibration isolating support device M in the engine rotation speed region corresponding to the roll resonance frequency. Suppresses body vibration.

  The operation will be described below with reference to FIGS.

  First, it is determined that the engine E has been stopped in step S11 of the flowchart of FIG. 6 showing the control when the engine E is stopped. The stop of the engine E here means not a state in which the rotation of the crankshaft is stopped, but a state in which the operation (explosion) of each cylinder is not performed, and the voltage of the engine ECU 10 is from 5V at the time of normal operation. Judged by 0V.

  In the subsequent step S12, a DC constant current (for example, 1 A) is applied to the actuator 41 of the active vibration isolating support apparatus M. Even if the engine E is stopped in the step S11, the crankshaft continues to rotate its inertia. Therefore, the engine E vibrates for a while and the active vibration isolating support device M expands and contracts, and the actuator 41 is driven by an external force. . As a result, an electromotive force is generated in the coil 34 of the actuator 41, and an alternating current having a frequency corresponding to the vibration frequency of the engine E is detected by the ammeter in step S13.

  In subsequent step S14, a region where the amplitude of the current is equal to or larger than a predetermined value, that is, a roll resonance region is extracted, and a roll resonance frequency is calculated from the frequency of the current in the roll resonance region. In step S15, the roll resonance frequency is updated for each loop and stored in the memory. In step S16, the application of the 1 A DC constant current to the actuator 41 is stopped.

  The reason why a 1 A DC constant current is applied to the actuator 41 in step S12 is that the current sensor detects an alternating current generated by an electromotive force of the coil 34 of the actuator 41 that is operated by supplying a current only in one direction. This is because a negative current cannot be detected. If a current sensor capable of detecting currents in both positive and negative directions is used, it is not always necessary to apply a DC constant current.

  Next, it is determined that the engine E is in the cranking state for starting in step S21 of the flowchart of FIG. It can be known from the crank pulse signal output from the crank pulse sensor Sa that the engine E is in the cranking state. In the subsequent step S22, the first explosion of the engine E is determined. The first explosion of the engine E can be known from a sudden decrease in the interval of the crank pulse signal, that is, a sudden increase in the crank angular velocity.

  In the subsequent step S23, it is determined which of the active vibration isolating support devices M, M on the front side and the rear side starts the control. The reason is that the first rolling direction of the engine E is determined by the situation such as which bank of the two banks Bf and Br the first explosion occurs. In subsequent step S24, the fluctuation of the engine speed is calculated in the same procedure as the flowchart of FIG. 4, and the stored roll resonance frequency is read in step S25. In the next step S26, the roll resonance amplitude is determined from the map search based on the engine speed variation, and in step S27, the roll resonance duration is determined from the map search based on the engine speed variation. In step S28, the driving of the actuator 41 is controlled based on the roll resonance frequency, the amplitude of the roll resonance, and the duration of the roll resonance, so that vibration at the start of the engine E can be suppressed.

  As apparent from FIG. 8, the roll resonance of the engine E occurs at the time of start and stop, and the cycle (frequency) of the roll resonance is the same between the roll resonance at the start and the roll resonance at the stop. However, the amplitude is much larger when starting than when stopping. Therefore, if the frequency of roll resonance is detected at the time of stop and the active vibration isolating support device M is controlled to suppress vibration due to roll resonance at the next start using the frequency, vibration due to roll resonance is effective as a whole. The active vibration isolating support device M is controlled by controlling the operation of the active vibration isolating support device M based on the latest natural frequency detected periodically. The anti-vibration effect can be exhibited effectively.

  When the engine E is started, the driver is sensitive to vibration because the driver pays attention to the engine rotation state (whether or not the engine is started). At that time, the active vibration isolating support device M is operated to roll By suppressing vibration due to resonance, the driver's sensible vibration suppression effect can be increased.

  FIG. 9 shows an actual roll vibration waveform when the engine E is stopped and a current waveform caused by the electromotive force of the actuator 41. As is apparent from this figure, it can be seen that the frequencies of the three waveforms immediately before the waveform where the amplitude of the actual roll vibration is maximized agree very well with the frequency of the corresponding current waveform.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.

  For example, the active vibration-proof support device M is not limited to a liquid-sealed device, and may use a piezo element.

  In the embodiment, the roll resonance frequency is detected when the engine E is stopped and the operation of the active vibration isolating support device M is controlled when the engine E is started. Conversely, the roll resonance frequency is set when the engine E is started. It may be detected and the operation of the active vibration isolating support device M may be controlled when the engine E is stopped.

  Further, each time the engine E is started and stopped a predetermined number of times, the roll resonance frequency is detected only once, and the active vibration isolation support device M is used both when the engine E is started and stopped using the roll resonance frequency. You may control the operation of.

  In the embodiment, the roll resonance frequency of the engine E is detected from the frequency of the current generated by the electromotive force of the actuator 41. However, the roll resonance frequency may be detected by an acceleration sensor provided in the engine E.

  In the embodiment, the active vibration isolating support apparatus M that supports the engine E of the automobile is illustrated, but the active vibration isolation support apparatus M of the present invention can be applied to support an engine other than the automobile.

  In the embodiment, roll resonance has been described as an example of rigid resonance, but the present invention can also be applied to resonance in the front-rear direction, the vertical direction, the left-right direction, the yaw direction, and the pitch direction.

Longitudinal section of active vibration isolator 2 enlarged view of FIG. The figure which shows the support form of the engine by the active type vibration proof support device Flow chart showing actuator control method during normal operation Explanatory drawing of step S5 of the flowchart of FIG. Flow chart showing the operation when the engine is stopped Flow chart explaining the operation at the time of engine start Diagram showing engine roll vibration waveform Diagram showing roll vibration waveform and current waveform when the engine is stopped

Explanation of symbols

E Engine M Active vibration isolation support device 41 Actuator

Claims (4)

In the natural frequency detection method of the engine for detecting the natural frequency of the rigid resonance of the engine (E) supported on the vehicle body via the active vibration isolation support device (M),
A method for detecting a natural frequency of an engine, wherein the natural frequency is detected when the engine (E) is started or stopped.   A current is generated by the electromotive force of the actuator (41) of the active vibration isolating support device (M) that is vibrated by the engine (E) at the time of start or stop, and the natural frequency is calculated from the frequency of the current. 2. The engine natural frequency detection method according to claim 1, wherein the detection is performed. A method for controlling an active vibration isolating support device using the method according to claim 1 or 2,
When the engine (E) is started or stopped, the operation of the active vibration isolating support device (M) is controlled based on the natural frequency to suppress rigid resonance of the engine (E). Control method of active vibration isolating support device.   Based on the natural frequency detected when the engine (E) is stopped, the operation of the active vibration isolating support device (M) is controlled when the engine (E) is started to suppress the rigid resonance of the engine (E). The method of controlling an active vibration isolating support device according to claim 3, wherein:

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