JP2011075514A - Engine bench - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine bench capable of preventing generation of malfunction caused by resonance, without causing degradation in the rotational speed trackability. <P>SOLUTION: The engine bench 10 includes a dynamometer 20 connected to an output shaft of an engine 11 via a shaft 21and a torque meter 24 for detecting the torque of the output shaft of the engine 11. The engine bench 10 keeps the shaft 21 fitted with a rotary-type oil damper 70 for absorbing the torsional vibration of the shaft 21 by utilizing a fluid. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an engine bench, and more particularly to an engine bench that performs high-precision measurement by suppressing shaft resonance.

  The engine bench is a test device that evaluates whether the developed and manufactured test engine has a predetermined performance. The engine to be tested is mounted on a bench test machine (engine bench) and its output shaft Is connected to the dynamometer via a torque meter or a tachometer. The dynamometer absorbs the rotational force of the output shaft of the engine to perform a bench test, and the performance of the engine is measured and evaluated.

  By the way, in such an engine bench, it is known that a resonance phenomenon occurs in any one of the rotation speed regions. When the resonance phenomenon occurs, there is a possibility that the measurement accuracy may be reduced or the apparatus may be damaged. . Therefore, various countermeasures have been conventionally taken. For example, in Patent Document 1, the resonance region is shifted by attaching a flywheel to the shaft in a detachable manner or by using a coupling having different rigidity. In Patent Document 2, the resonance point is set to be equal to or lower than the idling frequency, and in Patent Document 3, D2052 alloy, which is a vibration damping alloy, is provided between the drive side and the device under test.

JP-A-9-78616 Patent 3918435 JP 2006-162486 A

  However, Patent Documents 1 and 2 have problems such as a decrease in responsiveness in the rotation speed region used in the test. On the other hand, Patent Document 3 has a problem that the force other than the twisting direction is also attenuated, so that the rotational force is reduced and the speed followability to rotation is reduced.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an engine bench capable of preventing the occurrence of a malfunction due to resonance without deteriorating the rotational speed followability.

  In order to achieve the above object, the invention according to claim 1 is an engine bench including a dynamometer connected to an output shaft of an engine via a shaft. When the shaft rotates, the shaft is attached to the shaft. An engine bench comprising a rotary fluid damper that absorbs generated torsional vibrations by a fluid is provided. According to the present invention, since the rotary fluid damper is attached to the shaft, the torsional vibration of the shaft can be absorbed by the fluid damper, and the occurrence of problems due to resonance can be prevented.

  According to a second aspect of the present invention, in the first aspect of the invention, the fluid damper is formed in a hollow ring shape, the case through which the shaft is inserted and fixed to the shaft, and the case can be rotated in the case. And a ring-shaped inertial body provided in the cylinder, and oil filled in a gap between the inertial body and the case. In the fluid damper of the present invention, the case rotates as the shaft rotates, and the inertial body inside the case rotates following the case due to the viscosity of the fluid. According to the fluid damper having such a configuration, the torsional vibration of the shaft can be absorbed without deteriorating the rotational speed followability of the shaft. Therefore, the resonance of the shaft can be suppressed and an accurate engine test can be performed.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the shape of the fluid damper or the physical property of the fluid is obtained by analyzing a simulation result executed using a damper model obtained by modeling the fluid damper. It is determined by. According to the present invention, by analyzing the result of the simulation using the damper model, the shape of the appropriate fluid damper and the physical properties of the fluid are determined. Therefore, by using this fluid damper, the rotational speed followability is lowered. Therefore, the torsional vibration of the shaft can be surely prevented. In the case of the fluid damper having the configuration of claim 2, the shape of the fluid damper is the size (weight) of the inertial body, and the physical property of the fluid is the viscosity of the fluid.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a simulation unit that performs a simulation using a damper model obtained by modeling the fluid damper, a result of the simulation, and the fluid damper are used. And a verification unit that performs conformity with the result of the actual machine test performed. According to the present invention, the simulation result and the result of the actual machine test are compared and matched, so that the accuracy of the simulation can be confirmed. As a result, the damper model can be corrected to improve accuracy, and the shape of the fluid damper and the physical properties of the fluid damper can be corrected.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the invention includes a model creation unit that creates an engine model by an actual machine test of the engine, and the model creation unit is a damper that models the fluid damper. It is characterized by creating an engine model considering the model. According to the present invention, since the engine model is created in consideration of the damper model, the accuracy of the engine model can be improved.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, a ring-shaped concave portion or convex portion is formed on a side surface of the inertial body, and a concave portion or convex portion of the inertial body is formed on a side surface of the case. A ring-shaped convex portion or concave portion is formed opposite to. According to the present invention, since the concave portion or the convex portion is formed on the side surface of the inertial body and the side surface of the case, the contact area with the fluid is increased, and the vibration absorbing action by the fluid can be increased.

  According to the present invention, since the rotary fluid damper is attached to the shaft, the torsional vibration of the shaft can be absorbed by the fluid damper without deteriorating the rotational speed followability. Therefore, according to the present invention, it is possible to perform a highly accurate test while preventing the occurrence of defects due to resonance.

Schematic configuration diagram showing the engine bench of the present embodiment The perspective view which shows the structure of a fluid damper Partial sectional view of fluid damper Diagram showing the damper model The figure which shows the effect | action of the engine bench of this Embodiment

Hereinafter, preferred embodiments of an engine bench according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an engine bench according to the present embodiment.
The engine bench 10 shown in the figure is a device for measuring and evaluating the performance of the engine 11 to be tested, and mainly includes a dynamometer 20, a dynamometer control unit 30, an engine control unit 31, a measurement unit 40, and a model simulation unit 50. The system control unit 60 is configured.

  The engine 11 is fixed to the gantry 12 via a holding mechanism (not shown), and a combustion chamber (not shown) is provided inside the engine 11. An intake pipe 13 and an exhaust pipe 14 are connected to the combustion chamber. Air is sucked from the intake pipe 13 and exhaust gas after combustion in the combustion chamber is exhausted from the exhaust pipe 14. The intake pipe 13 is provided with a throttle 15, and the amount of air inflow is adjusted by the throttle 15. The exhaust pipe 14 is connected to a catalyst mounting portion 16 so that the exhaust gas can be purified by the catalyst mounted on the catalyst mounting portion 16.

  The output shaft of the engine 11 is connected to the dynamometer 20 via the shaft 21. The dynamometer 20 is a device that applies a predetermined load torque to the engine 11, and can set the load torque by varying the current and voltage. As the dynamometer 20, it is preferable to use a low inertia dynamometer. By using a low inertia dynamometer, a stable output corresponding to a sudden change in the rotational speed N from low speed rotation to high speed rotation can be obtained.

  The shaft 21 connecting the engine 11 and the dynamometer 20 is configured by connecting a plurality of shaft members such as a main shaft, and a universal joint 22 is interposed in the connecting portion. An intermediate bearing 23 is provided between the engine 11 and the dynamometer 20, and the shaft 21 is rotatably supported by the intermediate bearing 23. A torque meter 24 is provided on the engine 11 side of the intermediate bearing 23, and the torque of the shaft 21 is measured by the torque meter 24. In the present embodiment, the torque is measured by the torque meter 24. However, the present invention is not limited to this. For example, the torque may be detected from the output of the dynamometer 20. Further, in the present embodiment, the torque meter 24 is attached to the shaft 21, but in addition to this, a clutch, a transmission, various connecting means and the like may be inserted according to the purpose, and further, the engine 11 other than the torque may be inserted. For example, the temperature of the exhaust gas may be measured.

  An oil damper 70 is provided on the dynamometer 20 side of the intermediate bearing 23, and the torsional vibration of the shaft 21 is absorbed by the oil damper 70. In this embodiment, the oil damper 70 is provided between the intermediate bearing 23 and the dynamometer 20, but the mounting position of the oil damper 70 is not limited to this, and the oil damper 70 is provided between the intermediate bearing 23 and the engine 11. Or may be incorporated in a coupling member, intermediate bearing 23, shaft 21 or the like. The oil damper 70 is a feature of the present invention and will be described in detail later.

  The dynamometer 20 described above is connected to the dynamometer control unit 30. The dynamometer control unit 30 is means for variably controlling the current / voltage applied to the dynamometer 20, and the engine 11 connected to the dynamometer 20 is variably controlled by the dynamometer control unit 20. The load torque is controlled. Note that it is preferable to use a low inertia dynamometer as the dynamometer 20. In this case, the load torque detected by the dynamometer 20 and the shaft torque detected by the torque meter 24 are substantially the same.

On the other hand, each engine 11 is connected to an engine control unit 31. The engine control unit 31 is means for controlling the drive of the engine 11 by giving control parameters such as throttle opening and ignition advance to the engine 11, and is usually realized by an ECU or an engine control circuit in which a bypass circuit is added to the ECU. Is done. DSP (Digital) called virtual ECU instead of ECU
(Signal Processor). A control parameter (for example, a predetermined throttle opening) is given to the engine 11 by the engine control unit 31. As a result, the engine 11 rotates and the rotation is transmitted to the dynamometer 20 via the shaft 21. The control parameters given from the engine control unit 31 include the rotation speed, throttle opening, fuel injection amount, air injection amount, fuel / air mixture ratio, ignition time (in the case of a gasoline engine), fuel injection control. There are various parameters such as the method (in the case of a diesel engine).

  The engine control unit 31 and the torque meter 23 are connected to the measurement unit 40. The measurement unit 40 is a unit that inputs a signal indicating the operating state of the engine 11 and performs various types of signal processing, and mainly includes an input unit 41, a data memory 42, and a signal processing unit 43. The input unit 41 has an input circuit that takes in data from the engine control unit 31 and the torque meter 24, and controls data such as torque and rotation speed from the torque meter 24 and throttle opening degree from the engine control unit 31. Data is input. Note that the time series data such as the throttle opening may be directly input from the system control unit 50 described later, not from the engine control unit 31, or the engine control from the throttle opening detector provided in the engine 11. It may be input via the unit 31. In addition, when the input data is an analog signal, the input unit (measurement unit) 41 preferably performs A / D conversion to synchronize a plurality of input data with respect to time.

  Data input to the input unit 41 is temporarily stored in the memory 42. The memory 42 can also temporarily store data during signal processing in the signal processing unit 43 and data of signal processing results. Data stored in the memory 42 is signal-processed by the signal processing unit 43. The signal processing unit 43 is means for performing signal processing for determining an optimum value of a model created by the model creation simulation unit 50 described later. For example, a noise remover (filter), an adder / subtractor / divider for removing data noise , A differential integrator, an average value calculator, a standard deviation calculator, a data frequency counter (counter), a frequency analyzer (FFT), and the like.

  The model creation simulation unit 50 creates a model of the engine 11 based on the data obtained by the measurement unit 40, and performs simulation by controlling the engine control unit 31 and the dynamometer control unit 30 based on the created model. A model creation unit 51, a data memory 52, a simulation unit 53, and a verification unit 54.

  The model creation unit 51 is a unit that creates a model of the engine 11 and is based on the control parameter selected by the signal processing unit 43 and the data measured by the torque meter 24, and the relationship between any input and output ( A model expressing the transfer characteristic) with an expression, a graph or the like is created. The selection of the control parameter in the model creation unit 51 is not necessarily performed by the signal processing unit 43, and may be performed by the system control unit 60 or the model creation simulation unit 50. Further, the model created by the model creating unit 51 is not particularly limited, and there is, for example, an engine model that represents the relationship between the ignition advance angle and the load torque. Furthermore, the model creation by the model creation unit 51 may be created based on data obtained by tests in a steady state and a transient state. Here, the steady state is a state in which a parameter value (ignition advance angle in this embodiment) necessary to create a model is stabilized at a constant value for a certain period of time (for example, a parameter is changed stepwise). And a test performed by controlling parameters in this way is called a steady test. On the other hand, the transient state is a state in which the parameter value (ignition advance in this embodiment) necessary for creating the model is continuously changed in time (for example, the parameter is changed to a sine wave shape or a triangular wave shape). A test performed by controlling parameters in this way is called a transient test.

  The model created by the model creation unit 51 is stored in the memory 52. The simulation unit 53 performs a virtual simulation or a real machine simulation based on the model. In particular, the real machine simulation is performed while controlling the engine control unit 31 and the dynamometer control unit 30. The verification unit 54 compares the simulation result with the actual measurement value, verifies the validity / validity of the model, corrects the model, adjusts the parameter value, and the like.

The engine control unit 31, dynamometer control unit 30, measurement unit 40, and model creation simulation unit 50 described above are connected to the system control unit 60. The system control unit 60 is a means for performing various controls, and includes a definition unit 61 and an execution unit 62. The definition unit 61 has a function of setting various conditions of measurement contents. For example, control parameters such as accelerator opening, fuel injection timing, ignition advance, injection time, VVT, EGR, intake air temperature, exhaust gas temperature, Input / output status and input / output range of measurement parameters such as fuel injection amount, air injection amount, NO _X density, HC density, CO concentration, CO ₂ concentration, fuel consumption and water temperature can be set. . In the definition unit 61, frequently used setting conditions are registered in advance as standard actions. For example, a setting for changing the input conditions in a rectangular wave shape or gradually changing the input conditions in a step shape is set in advance. It is registered. The operator can easily set the measurement conditions by selecting from these standard actions. In addition to the standard action set in advance, the definition unit 61 has a function for freely creating a sequence. The sequence creation means is not particularly limited. For example, it is created by using a MATLAB-registered m-file or Simulink (registered trademark). By creating a sequence in this way, the operator can freely set the simulation conditions.

The input setting in the definition unit 61 is preferably set based on the experimental design method (DOE) or the central composite design (CCF). At that time, it is preferable to set so that the response surface can be sufficiently obtained by the output value. Further, the input interval (change width) of the control parameter does not have to be constant, and may be set so that the change width becomes small in the vicinity of the optimum point expected, for example. Further, the change width may be set smaller for a parameter having higher importance.
These operations in the definition unit 61 are performed using an operation unit 64 including a keyboard and a plurality of operation buttons. The conditions set by the definition unit 61 are stored in a memory (not shown).

  The execution unit 62 has a function of executing measurement, and is configured to execute measurement based on the condition (or sequence) set by the definition unit 61 described above. The system control unit 60 may include an automatic search function that automatically searches for a boundary value of a boundary error (for example, knocking or misfire). Further, an analysis device may be connected to the system control unit 60, an optimum point of the parameter measurement value may be formulated by the analysis device, and an ECU map may be created. At this time, the optimal point is not particularly limited, and for example, the optimal point may be determined by creating a response surface using the least square method.

  A display unit 65 is connected to the system control unit 60 described above. Various data stored in the memory 42, engine models stored in the memory 52, calculation results in the signal processing unit 43, simulation results in the simulation unit 53, and the like are displayed on the display unit 65. The display unit 65 displays various images such as a relationship graph, a trajectory, a frequency distribution table, and a standard deviation graph of a plurality of data. By displaying the simulation result on the display unit 65 in a graph, the robustness can be checked. The display unit 65 may simultaneously display a plurality of items such as data, maps, and graphs on the same screen.

  Next, the oil damper 70 which is a characteristic part of the present invention will be described. FIG. 2 is a perspective view showing the oil damper 70, in which a part of the case 71 is cut away to show the inside. FIG. 3 is a cross-sectional view taken along a plane passing through the rotation center of the oil damper 70.

As shown in these drawings, the oil damper 70 includes a case 71, an inertia body 72, and oil 73. The case 71 is formed in a ring shape, and the shaft 21 is inserted through the center of the case 71 and fixed to the shaft 21. Accordingly, the case 71 is also rotated as the shaft 21 is rotated.
A plurality of convex portions 71 </ b> A are formed on the inner surface of the case 71. The convex portions 71A are formed in a ring shape with the rotation axis of the case 71 as the center, and the convex portions 71A are formed at regular intervals. Thereby, the contact area of the oil 73 and case 71 which will be described later increases, and the damping coefficient which will be described later can be increased.

The inside of the case 71 is hollow, and a ring-shaped (doughnut-type) inertia body 72 is provided in the hollow portion. The inertia body 72 is rotatable with respect to the case 71, and the rotational force of the case 71 is transmitted to the inertia body 72 via an oil 73 described later.
A plurality of recesses 72 </ b> A are formed on the side surface of the inertial body 72. The recess 72A is formed in a ring shape around the rotation axis of the inertia body 72, and is formed to face the protrusion 71A of the case 71 described above. Thereby, the contact area of the oil 73 and the inertia body 72 which will be described later increases, and the damping coefficient which will be described later can be increased. In this embodiment, the convex portion 71A and the concave portion 72A are provided. However, the present invention is not limited to this, and the viscosity of the oil 73 is increased, or the gap amount between the case 71 and the inertial body 72 is decreased. Therefore, it is possible to adopt a configuration without the convex portion 71A and the concave portion 72A.

  The inside of the case 71 (that is, the gap between the case 71 and the inertial body 72) is filled with oil 73. The oil 73 having an appropriate viscosity is selected, and its suitability value is determined by the shape of the oil damper 70 and the inertia value of the equipment. For example, the oil 73 has a viscosity of about 3 to 50 Pa · s at room temperature (about 25 ° C.). Is used. By filling the oil 73, the rotational force of the case 71 is transmitted to the inertia body 72 via the oil 73. Note that it is preferable to provide the case 71 with a lid 71B as shown in FIG. The lid 71B is detachably provided on the case main body 71C, and is fixed to the case main body 71C by screws 74. Further, a packing 75 is disposed between the case main body 71C and the lid 71B to prevent the oil 73 from leaking. By configuring the oil damper 70 in this way, the oil 73 can be easily replaced.

  According to the oil damper 70 configured as described above, the case 71 rotates as the shaft 21 rotates, and the rotational force is transmitted to the inertial body 72 via the viscous oil 73, and the inertial body 72 is rotated. The During normal rotation, the case 71 and the inertial body 72 are in the same phase, and the rotational force of the shaft 21 is reliably transmitted. On the other hand, when resonance occurs, the phase of the inertial body 72 is delayed with respect to the phase of the case 71, and the viscosity of the oil 73 becomes resistance and the resonance amplitude of the shaft 21 is suppressed. That is, when resonance occurs, vibration energy is converted into thermal energy by the damping force due to the viscous resistance of the oil 73, and the amplitude of resonance is suppressed.

  The oil damper 70 is set so that a resonance magnification (a value obtained by dividing the amplitude of the torque output value by the input value) is equal to or less than a predetermined value as a suppression force of the amplitude of resonance. Thereby, the resonance which generate | occur | produces in the shaft 21 can be suppressed below to desired resonance magnification. Here, the predetermined value of the resonance magnification is preferably 3 or less, and by setting such a value, damage to the device due to resonance can be avoided. However, considering the effect of preventing damage to the apparatus, the upper limit of the resonance magnification is preferably as small as possible, and more preferably 2.5 or less.

  Here, considering the model of the oil damper 70 described above, the parameters that contribute to the resonance magnification are an inertia value (for example, the capacity of the inertial body 72) and a damping coefficient (also called a damping coefficient), and the shape of the oil damper 70 and the inertia of the equipment. For example, the viscosity of the oil 73 is determined according to the value. Therefore, it is important to set these two to appropriate values in order to set the resonance magnification below a predetermined value. Therefore, in this embodiment, the specification is determined by performing simulation and analyzing the result.

  The damper model used in the simulation can be obtained as follows. That is, assuming that the fluid (oil) in the case 71 is a laminar flow, the torque of the oil damper 70 is expressed by the following equation. In this equation, T is the torque, r1 is the inner diameter of the inertial body, r2 is the outer diameter of the inertial body, h is the gap between the inertial body and the case, ω is the rotational speed, and μ is the viscosity.

  Since the torsional rigidity between the dynamometer 20 and the oil damper 70 in the system of the engine 11, the oil damper 70, and the dynamometer 20 is relatively large, it is assumed to be integrated. If this is replaced with a spring-mass system for illustration, the result is as shown in FIG. In this equation, b is a damping coefficient.

  The characteristic equation in this system is as follows. In this equation, m1 is an inertia value of the engine 11, m2 is an inertia value of the dynamometer 20 and the oil damper 70, and k is a torsion spring constant.

m1 and m2 are predetermined values, and k is obtained by the following expression when the resonance frequency is R [Hz].

Therefore, if a necessary attenuation ratio is obtained, a value other than b is given, and b is obtained.
Next, considering the heat generated by the damper, the amount of heat generated by the damper is expressed by the following equation.

Here, if the real root of the characteristic equation is α (α <0), the root related to vibration can be obtained from the following equation.

  By performing a simulation using a damper model according to these equations and analyzing the result, a damping coefficient b (that is, an appropriate physical property of the oil, for example, the viscosity of the oil) and a spring constant k (the shape of the oil damper 70, for example, the inertia) Body volume) can be determined. In addition, after conducting an actual machine test using the determined oil damper 70, the test result and the simulation result may be matched and verified. As a result of the verification, if necessary, the damper model may be corrected, or the shape of the oil damper 70 and the physical properties of the oil 73 may be changed.

  Next, the operation of the engine bench 10 configured as described above will be described with reference to FIG. FIG. 5 shows the relationship between torque resonance magnification and frequency obtained from the test results. In the figure, the thick solid line is the result of the engine bench 10 of the present embodiment, the thin practice is the result of Comparative Example 1 without the oil damper 70, and the dotted line is the comparative example in which rubber is interposed in the power transmission portion. The result of 2.

  As shown in FIG. 5, in Comparative Example 1 without the oil damper 70, resonance occurs at the frequency a, and the resonance magnification is 3 or more. For this reason, resonance occurs at the frequency a, and the device may be damaged by the resonance. On the other hand, in Comparative Example 2, since the rubber is interposed in the power transmission portion, the spring constant is lowered and the resonance point is lowered to the frequency b. Therefore, if the frequency b is less than the idling frequency, resonance is not generated in the test at the idling frequency or higher, and a good test can be performed.

  However, in the case of the comparative example 2, since the resonance magnification itself is not lowered, the test at the frequency b cannot be performed at all. Further, Comparative Example 2 has a problem that it exhibits a behavior different from that of Comparative Example 1 in the frequency range immediately after exceeding the frequency b. In the vicinity of the frequency a, the gain drops drastically and a torque transmission delay occurs. There arises a problem that accuracy is lowered.

  On the other hand, since the engine bench 10 of the present embodiment is provided with the oil damper 70, the vibration is absorbed by the damping force due to the flow resistance of the oil 73, the resonance magnification itself in the resonance region is reduced, and 3 or less. It has become. Thus, according to the present embodiment, the resonance magnification can be suppressed to a set value or less, so that damage to the device due to resonance can be avoided.

  Further, according to the present embodiment, while the resonance magnification in the resonance region is lowered, the other frequency regions show almost the same tendency as in Comparative Example 1, and the resonance point is also the frequency a of Comparative Example 1. The frequencies c are substantially equal. Therefore, it is possible to reduce the resonance magnification while suppressing a decrease in measurement accuracy due to a torque transmission delay or the like.

  The configuration of the fluid damper in the present invention is not limited to the oil damper 70 described above, and various dampers using fluid can be used. For example, in the damper 70 described above, a plurality of spring components (for example, leaf springs, springs, rubber, etc.) are provided at predetermined angles inside the outer peripheral portion of the case 71, and the inertia body 72 is connected to the spring components. Good. Further, as a completely different configuration, a disk-shaped disk (substantially the same as an inertial body) is fixed to the shaft 21, a fixed case surrounding the disk is fixed to an intermediate bearing or the like, and oil is placed between the fixed case and the disk. A filled configuration may be used. In this case, since the fixed case does not move, it is suitable for connecting a cooling mechanism and a pressure adjusting mechanism described later. As another configuration, a disc-shaped disc is attached to the shaft 21 and a non-fixed case surrounding the disc is rotatably attached to the shaft 21 and oil 73 is filled between the non-fixed case and the disc. Good. In this case, the disk rotates as the shaft 21 rotates, and the non-fixed case rotates due to the flow resistance of the oil 73. Therefore, a damping force due to the flow resistance can be obtained, and the resonance magnification can be reduced.

  Although omitted in the above-described embodiment, a cooling mechanism for the oil 73 may be provided to suppress the temperature rise of the oil 73. As a cooling mechanism for the oil 73, for example, a method of providing a fan for blowing air on the outer surface of the case 71 or circulating a refrigerant through a jacket arranged so as to surround the case 71 can be considered. As another cooling method, a circulation path of oil 73 is connected to the case 71 via a rotary joint, and the oil 73 is used by an oil pump (impeller structure such as gear, vane, or bush thrust) arranged in the circulation path. It is conceivable to circulate the gas through the cooling device. At that time, the circulation amount and cooling amount of the oil 73 are preferably controlled in accordance with the heat generation amount and the rotational speed of the engine 11. As another method, a method of cooling the oil 73 by arranging one end of the Peltier element in the oil 73 and arranging the other end outside the case 71 and energizing it can be considered.

  Although omitted in the above-described embodiment, a pressure adjusting mechanism for the oil 73 may be provided. As a pressure adjustment mechanism for the oil 73, for example, a method of connecting a circulation path of the oil 73 to the case 71 and providing a pressure adjustment valve in the circulation path is conceivable as in the above-described cooling mechanism of the oil 73. As another method, a piezoelectric element may be provided inside the case 71, and a voltage may be applied to the piezoelectric element to increase or decrease the volume of the oil 73 to adjust the pressure.

  In the above-described embodiment, a viscosity adjusting mechanism that adjusts the viscosity of the oil 73 may be provided. As the viscosity adjusting mechanism, for example, a method of using an oil 73 of an electrorheological fluid and attaching a mechanism for applying an electric current to the oil 73 to the case 73 is conceivable. In this case, the viscosity of the oil 73 can be adjusted by passing an electric current through the oil 73. Another possible method is to use a magnetorheological fluid oil 73 and arrange a mechanism for applying a magnetic field to the oil 73 in the vicinity of the case 73. In this case, the viscosity of the oil 73 can be adjusted by applying a magnetic field to the oil 73.

  In the above-described embodiment, the damper model input in advance is used. However, the present invention is not limited to this. The damper model created by the model creation unit 51 based on the test result is used, or the verification unit 54 corrects the damper model. Alternatively, a damper model may be used.

DESCRIPTION OF SYMBOLS 10 Engine bench 11 Engine 20 Dynamometer 30 Dynamometer control part 31 Engine control part 40 Measurement part 50 Model simulation part 60 System control part 70 Oil damper 71 Case 72 Inertial body 73 Oil

Claims (6)

In an engine bench with a dynamometer connected to the output shaft of the engine via a shaft,
An engine bench comprising a rotary fluid damper attached to the shaft and absorbing torsional vibration generated when the shaft rotates by a fluid. The fluid damper is
A case formed in a hollow ring shape, the shaft being inserted and fixed;
A ring-shaped inertia body rotatably provided in the case;
Oil filled in a gap between the inertial body and the case;
The engine bench according to claim 1, further comprising:   The shape of the fluid damper or the physical property of the fluid is determined by analyzing a result of a simulation performed using a damper model obtained by modeling the fluid damper. Engine bench.   A simulation unit that performs simulation using a damper model obtained by modeling the fluid damper, and a verification unit that performs matching between the simulation result and the result of an actual machine test performed using the fluid damper. The engine bench according to any one of claims 1 to 3.   5. A model creation unit that creates an engine model by an actual machine test of the engine, wherein the model creation unit creates an engine model in consideration of a damper model obtained by modeling the fluid damper. The engine bench according to any one of the above. A ring-shaped recess or protrusion is formed on the side surface of the inertial body,
The engine bench according to any one of claims 1 to 5, wherein a ring-shaped convex portion or concave portion facing the concave portion or convex portion of the inertial body is formed on a side surface of the case.

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