JP2003207420A - Engine bench system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To resolve the problem of axial torque control and dynamo speed control avoiding the frequency of engine pulsation in engine-dynamo mechanical system. <P>SOLUTION: Gain theory transmission characteristics of mechanical system from an engine 1 to a dynamo meter 4 are obtained. From the theory transmission characteristics, a survey range of resonance frequency of the engine-dynamo mechanical system is determined. An upper device 12 torque-vibrates a controller 10. The transmission characteristics from the dynamo torque command to an axial torque detection value are obtained as measured gain characteristics. Based on a survey range for the measured gain characteristics, the peak value of the gain is obtained as the resonance frequency of the mechanical system and the gain value. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine bench system for performing various performance tests of an engine by directly connecting a dynamometer to the engine, and particularly to an engine-dynamo mechanical system. The present invention relates to a method for measuring a resonance frequency and the like. 2. Description of the Related Art FIG. 5 shows a conventional engine bench system.
As shown in the figure, the engine 1 and the transmission (AT or MT, in the case of MT, with clutch) 2 are combined,
It is connected to a dynamometer 4 via a shaft 3. [0003] The engine side is a throttle actuator (A
CT) 5 to control the throttle opening. A rotation detector 6 and a torque detector (load cell) 7 are provided on the dynamo 4 side, and the speed and torque of the dynamo 4 are controlled by the detection. With this system, durability and performance of the engine 1 (fuel consumption, exhaust gas measurement, etc.), ECU conformity, and other tests are performed. However, in such a system, the resonance point of the machine is low, so that torque cannot be transmitted from the dynamo side to the engine side with high response torque, or the high response behavior of the engine side is transmitted to the dynamo side. Therefore, there is a problem that the transient performance test of the engine and the vehicle-related parts cannot be performed unless the completed vehicle is used. As a means for solving such a problem, recently, as shown in FIG. 6, by directly connecting the engine 1 and the dynamo 4 with a high-rigidity shaft 8, a high frequency characteristic from the dynamo 4 to the engine 1 is obtained. A system that enables an engine test without a vehicle by performing torque reproduction up to the actual vehicle and performing transient reproduction in a state close to an actual vehicle has been considered. FIG. 7 shows a basic configuration diagram of a dynamometer control device of an engine bench system. For a mechanism in which the engine 1 and the dynamo 4 are mechanically coupled by the shaft 8, the engine torque is detected by the shaft torque meter 9 and the speed of the dynamo 4 is detected by a rotation detector (not shown).
The controller 10 performs an automatic control calculation using the dynamo speed or the shaft torque as a command value and the shaft torque detection value or the dynamo speed detection value as a feedback signal, and obtains a dynamo torque command as a calculation result. Inverter 1
1 is to drive the dynamo 4 with a current output according to the dynamo torque command from the controller 10 so that the dynamo 4 is driven.
, A torque corresponding to the dynamo torque command is generated. [0007] In the conventional engine bench system as shown in FIG. 5, the transmission frequency is set or the spring constant of the shaft is set low to reduce the resonance frequency of the target mechanical system by idling the engine. The rotation was set to be equal to or less than the rotation (for example, about 10 Hz). However, in a high response system such as that shown in FIG. 6, it is necessary to increase the frequency of the vibration torque applied to the engine.
It may be set to z or more. In such a case, the resonance frequency of the engine-dynamo mechanical system exists in the normal engine operation frequency range. Therefore, control is performed to avoid the resonance frequency or to control the gain at the resonance frequency. do. At that time, such an operation or control configuration cannot be adopted unless the resonance frequency is known. Conventionally, the measurement of the resonance frequency is usually performed by rotating the dynamo or engine at a low speed (less than the resonance frequency) and inputting the detected shaft torque to a spectrum analyzer to manually determine the resonance frequency. This is because torque pulsation is generated by the engine because the engine is rotating, and the frequency component is mixed in the detection of the shaft torque, so that it is difficult to determine the frequency component due to resonance. An object of the present invention is to provide an engine bench system capable of easily measuring a resonance frequency and a gain characteristic of a mechanical system even when there is engine pulsation. According to the present invention, a theoretical gain transfer characteristic of an engine-dynamo mechanical system is determined, and a search range of a resonance frequency of the engine-dynamo mechanical system is determined from the theoretical transfer characteristic. In advance, a torque is applied to the controller, a transfer characteristic from the dynamo torque command to the shaft torque detection value at this time is obtained as an actually measured gain characteristic, and the actual measured gain characteristic is determined based on the search range described above. The peak value of the gain is obtained as the resonance frequency and the gain value of the mechanical system, and is characterized by the following configuration. (1) In an engine bench system in which an engine and a dynamometer are connected by a shaft and various performance tests of the engine are performed by controlling a shaft torque of the engine or a dynamometer torque by a controller, the mechanical system of the engine-dynamometer is inertia Means for performing modeling as a system, solving the equation of motion of the model to obtain a theoretical gain transfer characteristic of the mechanical system, and determining a search range of a resonance frequency existing in the mechanical system from the theoretical transfer characteristic, When a random wave or sine wave dynamo torque command is given to the controller, a transfer characteristic from the dynamo torque command to the shaft torque detection value is obtained as an actually measured gain characteristic, and the actually measured gain characteristic is determined based on the search range. The peak value of the gain is sequentially calculated from the resonance frequency and the gain value of the mechanical system. Engine bench system comprising the means for. FIG. 1 is a configuration diagram of a measurement system showing an embodiment of the present invention. In the present embodiment, the resonance frequency and the gain characteristic of the engine-dynamo mechanical system are measured by using the existing dynamometer control device in the engine bench system. 12 is added. The host device 12 has a data input / output function and a data processing function based on a computer and its software configuration, and applies an axis torque command and a dynamo speed command to the controller 10 for testing an engine.
Thus, shaft torque control is performed by detection of the shaft torque meter 9 and speed control is performed by detection of the dynamo speed detector. In addition, the host device 12 measures the resonance frequency of the engine-dynamo mechanical system by applying a torque excitation command instead of the shaft torque command or the dynamo speed command to the controller 10. FIG. 2 shows a measurement flow of the host device 12. First, the host device 12 inputs a theoretical gain transfer characteristic from a dynamo torque command to a shaft torque detection in the engine-dynamo system targeted this time (S1). In this input, a transfer characteristic waveform is input in the form of a transfer function. As shown in FIG. 3, this characteristic can be calculated from a model of the engine-dynamo mechanical system as a three-inertia system and the equation of motion of this model. FIG.
Shows an example of the gain theoretical transfer characteristic, and there are two resonance frequencies. Next, the host device 12 determines a range for searching for a resonance frequency from the input gain theoretical transfer characteristic (S2). For example, ± 10 of the determined theoretical resonance frequency
Set like%. Next, the engine-dynamo system is operated at a constant rotation away from the resonance frequency, and a torque excitation command is given from the host device 12 to the controller 10 (S3). This excitation may be random or a sine wave may be swept by changing the frequency. Next, a dynamo torque command value and a shaft torque detection value at the time of vibration are collected from the controller 10 and the shaft torque meter 9 (S4). Next, using the dynamo torque command value and the shaft torque detection value, the host device 12 obtains a transmission characteristic using the input to the controller 10 as the dynamo torque command value and the output as the shaft torque detection value. As a characteristic, an actually measured gain characteristic from a dynamo torque command value to a shaft torque detection value is obtained (S5). Next, a search is performed based on the search range previously determined from the gain characteristics, a peak value of the gain is sequentially calculated, a resonance frequency and a gain value at that time are obtained (S6), and this is output. (S7). This calculation is performed up to the secondary resonance frequency point in the case of the gain theoretical transfer characteristic using FIG. Therefore, in this embodiment, since the frequency component due to the engine pulsation is outside the search range, only the resonance frequency can be accurately calculated. As described above, according to the present invention, the theoretical gain transfer characteristic of the engine-dynamo mechanical system is determined, and the search range of the resonance frequency of the engine-dynamo mechanical system is determined from the theoretical transfer characteristic. Is determined, the torque is applied to the controller, and the transmission characteristic from the dynamo torque command to the shaft torque detection value at this time is determined as the actually measured gain characteristic, and the actual measured gain characteristic is determined based on the above search range. To obtain the peak value of the gain as the resonance frequency and the gain value of the mechanical system.
In a dynamo-based mechanical system, even if there is an engine pulsation, the resonance frequency and gain of the mechanical system can be accurately calculated excluding this frequency range.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a measurement system showing an embodiment of the present invention. FIG. 2 is a measurement flow in the embodiment. FIG. 3 is a conceptual diagram of an engine-dynamo mechanical system model. FIG. 4 is an example of gain characteristics from a dynamo torque command to shaft torque detection. FIG. 5 is a configuration diagram of a conventional engine bench system. FIG. 6 is another conventional system configuration diagram. FIG. 7 is a configuration diagram of a dynamometer control device. [Description of Signs] 1 ... Engine 4 ... Dynamometer 8 ... Shaft 9 ... Shaft Torque Meter 10 ... Controller 11 ... Inverter 12 ... Host Device

Claims (1)

Claims: 1. An engine bench system in which an engine and a dynamometer are connected by a shaft, and various performance tests of the engine are performed by an engine shaft torque control or a dynamometer torque control by a controller. Modeling the mechanical system as an inertial system, solve the equation of motion of this model to determine the gain theoretical transfer characteristic of the mechanical system, and determine the search range of the resonance frequency existing in the mechanical system from this theoretical transfer characteristic. Means, and a transfer characteristic from the dynamo torque command to the shaft torque detection value when a random wave or sine wave dynamo torque command is given to the controller is obtained as an actually measured gain characteristic. The peak value of the gain is determined based on the search range and the resonance frequency and the gain of the mechanical system. Means for sequentially calculating the in-values.