JP2008203052A - Control device for engine bench system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein the vibration due to pulsating torque of an engine is superimposed and adversely affects the actual axial torque detection, depending on driving conditions in an engine bench system. <P>SOLUTION: A band filter circuit for filtering out vibration components due to the torque variation of the engine is connected to the front stage of a torque control part for a dynamometer. The band-filter circuit is provided with a converter passing a rotational speed signal, and the constant of the converter is set at the constant that corresponds to the filtration of main frequency components of the torque variations of the engine. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for an engine bench system, and more particularly to a control device that suppresses generation of vibration caused by engine pulsation torque.

  The engine bench system includes an engine, a clutch, a propeller shaft, a shaft torque meter, a dynamometer, and the like, and performs tests such as an engine durability test, fuel consumption, and exhaust gas measurement while performing torque control of the dynamometer. Patent Document 1 is known as such an engine bench system.

  FIG. 11 is a block diagram of the engine bench system control device disclosed in Patent Document 1. A dynamometer 4 is connected to the engine 1 via a shaft 2 and a shaft torque meter 3, and this dynamometer 4 is driven by an inverter 5. Is done. A vehicle model unit 6 includes, for example, a four-inertia spring model and a vertical vibration model using a suspension and a tire spring, and outputs an engine load torque command to the torque control unit 7. The torque control unit 7 calculates a torque current command based on the engine load torque command value input from the vehicle model unit 6 and the detected rotational speed signal and shaft torque signal, and according to the output. The dynamometer 4 is controlled through the inverter 5.

An engine inertia model unit 8 calculates (1 / (Je · s)) in the model unit, and outputs it to the vehicle model unit 6 and the subtracting unit 11 as an engine model speed signal. In the subtractor 11, a difference calculation between the dynamometer or engine speed detection signal and the engine model speed signal is executed, and the deviation signal is output to the controller 9. As the transfer function G (s) of the controller 9, for example, an arbitrary controller having integral characteristics or proportional characteristics such as a PI controller (Kp + Ki / s) is used.
Here, Je is the moment of inertia of the engine, Kp is a proportional coefficient, and Ki is an integral coefficient.

The output of the controller 9 is added to the output of the engine torque map 10 in the adding unit 12 and output to the adding unit 13, and is added to the engine load torque command value in the adding unit 13 and output to the engine model unit. The engine torque map 10 stores a graph of the relationship between the engine speed, throttle opening, and engine torque characteristics prepared in advance by measurement. When the engine test is started, the detected speed signal of the dynamometer (or engine) and the throttle opening signal are input to the engine torque map 10, and the engine torque is estimated from the input signal and output to the adder 12. .
JP 2004-177259 A

  In the engine bench system, a response delay of the torque control unit 7 occurs due to mechanical factors, and an unstable phenomenon such as hunting occurs due to this response delay. However, the control device shown in FIG. Has an effect. However, when the engine generates a large engine pulsation torque, such as a large diesel engine, the vibration due to the engine pulsation torque is superimposed on the engine load torque command from the vehicle model unit 6, and the vibration may actually vary depending on the operating conditions. There is a possibility that even the shaft torque detection value is vibrated.

  Accordingly, an object of the present invention is to provide a control device for an engine bench system that enables stable control even in the case of a large engine.

In the first aspect of the present invention, an engine and a dynamometer are directly connected via a shaft, and an engine model speed signal generated by the engine inertia model speed unit is output to the vehicle model unit to calculate an engine load torque command value. The calculated value is output to the torque control unit, and the torque current command value is obtained using the engine load torque command value input to the torque control unit, the detected shaft torque and the rotational speed signal of the dynamometer. In an engine bench system that controls a dynamometer by outputting a command value to an inverter,
A band removal filter circuit for removing vibration components caused by torque fluctuations of the engine is connected to the front stage of the torque control unit. Control device for engine bench system.

  According to a second aspect of the present invention, a converter that passes the rotational speed signal is provided in the band removal filter circuit, and the constant of the converter is set to a constant corresponding to remove a main frequency component of engine torque fluctuation. It is characterized by that.

  A third aspect of the present invention is a case where the band elimination filter circuit is connected in a plurality of stages, and the main frequency component of the engine torque fluctuation is an integer multiple of the engine speed, and a plurality of torque fluctuation components corresponding to the integer multiple frequency. It is characterized in that it is configured to remove the.

  According to a fourth aspect of the present invention, the detected shaft torque signal and rotation speed signal are input to an engine torque observer to estimate the engine torque, and the estimated engine torque estimated value and the engine load torque command value are calculated. A deviation is obtained, and a model speed signal of the engine is generated based on the deviation value.

  According to a fifth aspect of the present invention, a deviation value between the engine model speed signal and the detected rotation speed signal is calculated and output to a torque estimation value correction unit of the engine, and the torque estimation value correction unit responds to the deviation value. A correction value is generated and added to the output value of the torque observer.

  According to a sixth aspect of the present invention, the detected rotational speed signal and the engine throttle opening signal are input to an engine torque map to estimate the engine torque, and the estimated engine torque estimated value and the engine load torque command A deviation from the value is obtained, and a model speed signal of the engine is generated based on the deviation value.

  According to a seventh aspect of the present invention, a deviation value between the engine model speed signal and the detected rotation speed signal is calculated and output to a torque estimation value correction unit of the engine, and the torque estimation value correction unit responds to the deviation value. A correction value is generated and added to the output value of the torque map.

As described above, according to the present invention, the band removal filter circuit for removing the vibration component due to the torque fluctuation of the engine is provided in the front stage of the torque control unit, thereby corresponding to the torque fluctuation frequency of the engine. Only the vibration frequency can be removed. For this reason, a torque current command in which the pulsating torque of the engine is not superimposed is generated, and a stable operation of the engine bench system can be realized.
In addition, by using a multi-band band elimination filter circuit, high-precision control is possible even when there are a plurality of main frequency components of engine torque fluctuations, and stable engine bench system operation can be realized. .

According to the present invention, pulsation is suppressed by outputting an engine load torque command calculated by a vehicle model unit to a torque control unit via a filter circuit. FIG. 2 shows a band elimination filter circuit 20 that is commonly used in each embodiment. 21 to 24 are converters each having constants A to D, 25 is a multiplier, 26 is an integrator, Reference numerals 27 and 28 denote adders. The constants (A, B, C, D) in each converter are the ABCD matrices of the continuous state equation expression of the band removal filter having 1 [rad / s] as the characteristic frequency.
The continuous system equation of state is expressed by dx / dt = A · x + B · u and y = C · x + D · u.
FIG. 3 is an example of a Bode diagram of a band elimination filter having 1 [rad / s] as a characteristic frequency.

In general, the main vibration source of an engine bench system is a torque fluctuation generated by the engine. The frequency of engine torque fluctuation is generally proportional to the engine speed, and has a frequency of, for example, 2 or 4 times the engine speed, or 0.5 or 1.5 times in some cases.
Conventionally, torque fluctuations of these frequencies are superimposed on shaft torque detection or dynamometer rotation speed detection, and an engine load torque command is entered by a closed loop of the control device to generate a vibration phenomenon.

  FIG. 1 shows a configuration diagram of a control device of an engine bench system showing an embodiment of the present invention. The same reference numerals are given to the same or corresponding parts as in FIG.

  In the configuration shown in FIG. 1, the engine 1 is controlled by a control circuit (not shown) so that there is no deviation between the throttle opening command and the detected throttle opening signal. In the torque control unit 7, a torque current command is generated based on the engine load torque command value from the vehicle model unit 6 input through the band removal filter circuit 20, the detected rotation speed signal, and the shaft torque signal. And the dynamometer 4 is controlled via the inverter 5 according to the output.

  A rotational speed signal of the dynamometer 4 (or engine) is detected by an encoder or the like, and is input to the torque observer 30 and the band removal filter circuit 20 of the engine. The detected shaft torque signal is also input to the torque observer 30, the engine torque is estimated from the rotational speed signal and the shaft torque signal, and the estimated value is output to the subtractor 31. In the subtracting unit 31, the difference between the engine torque estimation signal and the engine load torque command from the vehicle model unit 6 is executed, and the deviation signal is output to the engine inertia model unit 8 to calculate the engine model speed signal. .

  The vehicle model unit 6 calculates an engine load torque command based on the input model speed signal of the engine and outputs it to the subtracting unit 31 and the band removal filter circuit 20. The band removal filter circuit 20 is configured as shown in FIG. 2, and outputs an engine load torque command by the converters 22 and 24 multiplied by a constant BD, respectively. The output of the converter 22 is added to the output of the adder 21 of the constant A by the adder 27, and the added value is multiplied by the speed signal of the dynamometer (or engine) input through the converter 29 in the multiplier 25. . The multiplication value is integrated by the integrator 26 and then added to the output of the converter 24 by the adder 28 and output to the torque control unit 7.

  Since the frequency characteristic of the band elimination filter circuit 20 has a characteristic as shown in FIG. 3, for example, it has a characteristic that only the vicinity of 10 [rad / s] is greatly attenuated, and is not attenuated in other frequency ranges. The characteristic is maintained and the pulsation waveform of 1 [rad / s] is removed. Therefore, a torque command without pulsation is input to the torque control unit 7.

  Here, for example, when the torque fluctuation frequency of the engine is the main component of twice the engine speed, setting the constant N of the converter 29 for converting the speed signal of the dynamometer to N = 2 causes a problem. Only the frequency of the vibration is removed by the band removal filter circuit 20 having the characteristics shown in FIG. For this reason, since the engine load torque command on which the pulsating torque of the engine is not superimposed is input to the torque control unit 7, a torque current command that enables high-precision control is generated, and stable engine bench system operation is performed. realizable.

  FIG. 4 shows the configuration of Embodiment 2 of the present invention. The difference from the embodiment shown in FIG. 1 is that an estimated value correction unit 40 for engine torque is added, and a subtraction unit for subtracting the difference between the dynamometer (or engine) speed signal and the model speed signal from the engine inertia model unit 8. The engine torque estimated value is corrected based on the deviation between the actual speed and the model speed. The correction signal is added to the output signal from the engine torque observer 30 in the adder 32 and then output to the subtractor 31.

  In this embodiment, in addition to the vibration component from the engine torque observer 30, the estimated value correction is performed by the torque estimated value correction unit 40, and the vibration component is added to the engine load torque command via the vehicle model unit 6. However, even in this case, the operation of the band removal filter circuit 20 makes it possible to remove vibration components due to engine torque fluctuations, and a stable engine bench system operation can be realized as in the first embodiment.

  FIG. 5 shows the configuration of the third embodiment of the present invention. The difference from the embodiment shown in FIG. 1 is that an engine torque map 10 is provided instead of the engine torque observer 30, and an engine throttle opening signal and a speed signal are input. The engine torque map 10 does not directly measure the engine torque during the test operation of the engine, but is a graph showing the relationship between the engine speed, the throttle opening, and the engine torque characteristics prepared in advance. It is.

  During the engine test operation, the detected engine or dynamometer speed signal and the throttle opening signal of the throttle actuator are input, the engine torque is estimated from these input signals, and the estimated value is input to the subtractor 34. The deviation from the engine load torque command value is calculated. Based on this deviation value, an inertia model unit 8 generates a model speed value of the engine.

  According to this embodiment, the engine torque map 10 is used in place of the torque observer 30 as compared with the first embodiment, so that the engine torque fluctuation component superimposed on the shaft torque is used as the engine load torque command. However, the torque fluctuation of the engine superimposed on the dynamometer speed signal input to the torque map 10 is transmitted to the engine load torque command value. However, also in this case, the vibration component caused by the engine torque fluctuation is removed by the band removal filter circuit 20, and a stable operation of the engine bench system can be realized.

  FIG. 6 shows the configuration of Embodiment 4 of the present invention. The difference from the embodiment shown in FIG. 5 is that an estimated value correction unit 40 for engine torque is added, and a difference between the speed signal of the dynamometer (or engine) and the model speed signal from the engine inertia model unit 8 is subtracted. The engine torque estimated value is corrected based on the deviation between the actual speed and the model speed. The correction signal is added to the output signal from the engine torque map 10 in the adder 35 and then output to the subtractor 34.

In this embodiment, the torque fluctuation is added from the engine torque map 10,
It is transmitted to the engine load torque command value through the correction value from the estimated value correction unit 40 of the engine torque. The transmitted torque fluctuation is removed by the band removal filter circuit 20, and a stable operation of the engine bench system can be realized.

  FIG. 7 shows another example in which the band elimination filter circuit 20 shown in FIG. 2 has a two-stage configuration of 20-1 and 20-2. Since the filter circuit shown in FIG. 2 has one stage, the frequency that can be removed is only one component, but in FIG. 7, the two-stage configuration enables frequency removal of two components. In this case, for example, if the main component of the engine torque fluctuation is twice or four times the engine speed, the constants N1 and N2 of the converters 29-1 and 29-2 of the filter circuit are set to N1. By setting = 2, N2 = 4, or N1 = 4, N2 = 2, it is possible to remove torque fluctuation components having both frequency components twice and four times the engine speed. Of course, the number of stages of the filter circuit can be arbitrarily selected instead of only two.

  By using the band removal filter circuit 20a configured as shown in FIG. 7 in place of each of the band removal filter circuits 20 shown in the first to fourth embodiments, vibration components caused by engine torque fluctuations having a plurality of frequencies are used. Can be removed.

  8 to 10 are operation waveform diagrams of the engine bench system based on the verification of the present invention. 8 shows a case where the filter circuit shown in the first to fourth embodiments has one stage, and FIG. 9 uses a two-stage band elimination filter circuit 20a in place of the band elimination filter circuit 20 in the configuration of FIGS. 1 and 4-6. FIG. 10 shows the operation waveform of the conventional engine bench system shown in FIG. 11, where (a) shows the relationship between the rotational speed and time of the dynamometer, and (b) shows the relationship between the shaft torque and time. FIG. 4C is a diagram showing the relationship between shaft torque command frequency and time.

  In the prior art shown in FIG. 10, the standard deviation (value indicated by std in the figure) of the shaft torque command value is about 35. On the other hand, the standard deviation of the shaft torque command value in the present invention shown in FIG. Further, as shown in FIG. 9, the standard deviation of the shaft torque command value when the two-stage band elimination filter circuit 20a is used is reduced to about 4, and the effect of the present invention was confirmed.

The operation waveform shown in FIG. 8 is when N of the converter 29 shown in FIG. 2 is N = 1, and the operation waveform in FIG. 9 is N1 of the converter 29-1 shown in FIG. = 0.5 and N2 = 1.
Each of FIGS. 8 to 10 shows the distribution of the vibration frequency of the shaft torque command value. The vibration frequency component of the shaft torque command value corresponding to the selected N or N1, N2 is shown in FIG. It turns out that it is reducing.

The block diagram which shows embodiment of this invention. The block diagram of the band removal filter circuit used for this invention. The characteristic diagram of a band removal filter circuit. The block diagram which shows other embodiment (Example 2) of this invention. The block diagram which shows other embodiment (Example 3) of this invention. The block diagram which shows other embodiment (Example 4) of this invention. The block diagram of the band removal filter circuit of 2 steps | paragraphs structure. FIG. 4 is an operation waveform diagram of the engine bench system according to the present invention, where (a) is a dynamometer rotational speed-time relationship diagram, (b) is an axial torque-time relationship diagram, and (c) is an axial torque command frequency-time relationship diagram. FIG. 4 is an operation waveform diagram of the engine bench system according to the present invention, where (a) is a dynamometer rotational speed-time relationship diagram, (b) is an axial torque-time relationship diagram, and (c) is an axial torque command frequency-time relationship diagram. FIG. 4 is an operation waveform diagram of a conventional engine bench system, in which (a) is a dynamometer rotation speed-time relationship diagram, (b) is a shaft torque-time relationship diagram, and (c) is a shaft torque command frequency-time relationship diagram. The block diagram of the conventional engine bench system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Shaft 3 ... Shaft torque meter 4 ... Dynamometer 5 ... Inverter 6 ... Vehicle model part 7 ... Torque control part 8 ... Engine inertia model part 10 ... Torque map 20 ... Band removal filter circuit 30 ... Engine torque observer 40 … Engine torque estimated value correction unit

Claims (7)

The engine and dynamometer are directly connected via a shaft, the engine model speed signal generated by the inertia model speed part of the engine is output to the vehicle model part to calculate the engine load torque command value, and the calculated value is torque controlled The torque current command value is obtained using the engine load torque command value input to the torque control unit, the detected shaft torque and the rotational speed signal of the dynamometer, and the torque current command value is output to the inverter. In the engine bench system that controls the dynamometer by
A control device for an engine bench system, wherein a band removal filter circuit for removing vibration components caused by torque fluctuations of the engine is connected to a front stage of the torque control unit. The converter for passing the rotational speed signal is provided in the band removal filter circuit, and the constant of the converter is set to a constant corresponding to remove a main frequency component of engine torque fluctuation. 1. The control device for the engine bench system according to 1. The band removal filter circuit is connected in a plurality of stages, and when the main frequency component of engine torque fluctuation is an integer multiple of the engine speed, a plurality of torque fluctuation components corresponding to the integer multiple frequency are removed. The engine bench system control device according to claim 2, wherein The detected shaft torque signal and rotational speed signal are input to an engine torque observer to estimate the engine torque, and a deviation between the estimated engine torque estimated value and the engine load torque command value is obtained. The engine bench system control device according to any one of claims 1 to 3, wherein a model speed signal of the engine is generated on the basis of the engine speed signal. A deviation value between the engine model speed signal and the detected rotational speed signal is calculated and output to a torque estimation value correction unit of the engine, and a correction value corresponding to the deviation value is generated by the torque estimation value correction unit. 5. The engine bench system control device according to claim 4, wherein the control device is added to an output value of a torque observer. The detected rotation speed signal and the engine throttle opening signal are input to an engine torque map to estimate the engine torque, and a deviation between the estimated engine torque estimated value and the engine load torque command value is obtained, The engine bench system control device according to any one of claims 1 to 3, wherein a model speed signal of the engine is generated based on the deviation value. A deviation value between the engine model speed signal and the detected rotational speed signal is calculated and output to a torque estimation value correction unit of the engine, and a correction value corresponding to the deviation value is generated by the torque estimation value correction unit. 7. The engine bench system control device according to claim 6, wherein the control device is added to an output value of a torque map.