JP2004177259A - Controller for engine tester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in an engine tester for simulating a load by using a controller having a vehicle model part and a torque control part, that an unstable phenomenon appears in engine speed when a response is slow in a closed loop of a shaft torque control system relative to a closed loop of the model part. <P>SOLUTION: The engine model part is provided for outputting a model speed signal for an engine, a deviation between the model speed signal and a detected engine speed signal is inputted into the controller, and its output and a load torque command value from the vehicle model part are added together and outputted to the engine model part. The engine model part is structured to generate the model speed signal based on the inputted signal and to output it to the vehicle model part, thereby improving the closed loop characteristics of the entirety including the vehicle model part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a test device for an engine, and particularly to a control device in the test device.
[0002]
[Prior art]
FIG. 5 shows a configuration diagram of a control device in the engine test apparatus. A dynamometer 4 is connected to an engine 1 via a shaft 2 and an axial torque meter 3, and the dynamometer 4 is driven by an inverter 5. Reference numeral 6 denotes a vehicle model, which comprises, for example, a four-inertia spring model and a vertical vibration model based on suspension and tire springs, and inputs a detected dynamometer speed signal or an engine speed signal and outputs an engine load torque command. It is output to the torque control unit 7 as (control point torque command).
[0003]
The torque control unit 7 calculates a torque current command value based on the input torque command, the detected shaft torque signal from the shaft torque meter 3 and the detected speed signal from the dynamometer 4, and sends the signal to the inverter 5. Output. Inverter 5 is subjected to torque current control so that the detected shaft torque signal follows the torque command value, and simulates the load characteristics of the engine.
As a control device in an engine test device for simulating the load characteristics of the engine, Patent Document 1 and the like are known.
[0004]
[Patent Document 1]
JP-A-2002-98617 (FIGS. 1 to 4 and description thereof)
[0005]
[Problems to be solved by the invention]
In the control device shown in FIG. 5, a closed loop for controlling torque of the shaft torque detection value → torque control unit 7 → inverter 5 → dynamometer 4 → shaft torque meter 3 is formed. On the outside, a closed loop including the speed of the dynamometer 4 (or the engine 1) → the vehicle model unit 6 → the torque control unit 7 → the speed detector (or the engine speed detector) of the dynamometer is formed.
[0006]
As described above, when the control device is configured by two closed loops, if the control response of the closed loop of the torque control system provided inside is slow, the load torque command value output from the vehicle model unit 6 may actually be changed. As a result, the load torque applied to the engine 1 is delayed, and as a result, the engine speed does not operate properly, and in some cases, a hunting phenomenon or runaway of the engine speed is caused as shown in FIG. It becomes.
[0007]
FIG. 6 shows a simulation result when the frequency response of the torque control unit is 7 Hz and the gain is -3 dB in the control device of FIG. According to this, an appropriate engine test is performed until about time 12 seconds, but after 12 seconds, the dynamometer torque shows an inappropriate vibration phenomenon, and as a result, the target engine test cannot be performed. Have a problem.
[0008]
According to Patent Document 1, due to the effect of pulsating torque generated by the engine, an error occurs because the actual engine torque during the operation of the engine bench system does not match the estimated value output by the torque map. Although a solution based on the inability to perform a high-precision simulation operation due to the influence is disclosed, the response delay of the torque control system is not mentioned.
[0009]
An object of the present invention is to provide a control device of an engine test apparatus in which a control failure based on a response delay is eliminated.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, an engine and a dynamometer are directly connected via a rotating shaft, a rotation speed signal of the engine or the dynamometer is detected and introduced into a vehicle model unit. A torque current command value is generated and output to the torque control unit, and a torque current command value is obtained using the load torque command value introduced by the torque control unit, the detected shaft torque value, and the rotation speed signal. In controlling the dynamometer via an inverter according to the value,
An engine model unit that generates a model speed signal of the engine and outputs it to a vehicle model unit, and a controller that inputs a deviation between the model speed signal of the engine and the rotation speed signal and converts the deviation into a torque signal, The output signal of the controller and the load torque command value of the engine from the vehicle model unit are added and output to the engine model unit, and the engine model unit calculates the model speed signal of the engine. Things.
[0011]
A second aspect of the present invention is characterized in that the engine model section outputs an engine model speed signal calculated by 1 / (Je · s).
Here, Je is the moment of inertia of the engine.
[0012]
A third aspect of the present invention is characterized in that the controller is a controller having an integral characteristic or a proportional characteristic.
[0013]
A fourth aspect of the present invention is to provide an engine torque map which represents the relationship between the engine speed, the throttle opening and the engine torque characteristic prepared in advance and prepares the throttle opening signal of the throttle actuator and the rotation speed signal in the engine torque map. To estimate the engine torque value, add the estimated value and the output value of the controller, add the addition signal and the load torque command value of the engine, and output the result to the engine model unit. It is characterized by the following.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing an embodiment of the present invention. The same or corresponding portions as those in the conventional block diagram shown in FIG.
Reference numeral 11 denotes a controller. As the transfer function G (s) in the controller 11, an arbitrary controller having an integral characteristic or a proportional characteristic such as a PI controller (Kp + Ki / s) is used. An engine model 12 outputs an engine model speed signal calculated by (1 / (Je · s)).
Here, Kp is a proportional coefficient, Ki is an integral coefficient, and Je is a moment of inertia of the engine.
Reference numerals 13 and 14 denote adders, respectively.
[0015]
In the configuration described above, the engine 1 is controlled by a control circuit (not shown) so that the deviation between the throttle opening command and the detected throttle opening signal is eliminated.
The torque control unit 7 calculates a torque current command based on the input engine load torque command value from the vehicle model unit 6 and the detected rotation speed signal and shaft torque signal. To control the dynamometer 4 via the inverter 5.
[0016]
The rotation speed of the dynamometer 4 (or the engine) is detected by an encoder or the like and applied to the adding unit 13. An engine model speed signal from the engine model unit 12 is applied to the addition unit 13. Both signals are added with different polarities in the addition unit, and a deviation signal thereof is input to the controller 11 to output a torque signal. And outputs the result to the adding unit 14.
The load torque command value of the engine from the vehicle model unit 6 is applied to the adder unit 14. Therefore, the adder unit 14 adds the two signals to the same polarity, and then inputs the signals to the engine model unit 12 to input the signals to the engine model unit 12 and add Find the model speed signal. The model speed signal is applied to the adding unit 13 and also applied to the vehicle model unit 6 as a speed signal, and used for calculating a load torque command value of the engine.
[0017]
2A and 2B show simulation results of the control device of FIG. 1, wherein FIG. 2A is a torque diagram of a dynamometer, and FIG. 2B is a speed diagram of an engine. As is apparent from FIG. 2, inappropriate vibration in the dynamometer torque and the engine speed as in the related art shown in FIG. 6 does not occur, and the closed-loop characteristics of the entire control system are improved. Therefore, even when the response of the closed loop of the shaft torque control system is slow, the engine test can be performed by the closed loop having the vehicle model outside the closed loop.
[0018]
FIG. 3 shows a configuration diagram of another embodiment. In the figure, an engine torque map 20 is provided in the embodiment shown in FIG. The added signal is added to the load torque command value in the adding unit 14 and input to the engine model unit 12.
The engine torque map 20 does not directly measure the engine torque during the operation of the engine test apparatus, but is a graph showing the relationship between the engine rotation speed, the throttle opening, and the engine torque characteristics prepared in advance and prepared. During the operation of the engine test apparatus, the detected dynamometer speed or the engine speed and the throttle opening signal of the throttle actuator are input to the engine torque map 20, and the engine torque is estimated from these input signals. The signal is output to the addition unit 21 and added to the output G (s) of the controller 11. Others are the same as FIG.
[0019]
According to the embodiment shown in FIG. 3, by adding the engine torque map, even if the response of the output G (s) of the controller 11 having the integral characteristic is slow, the engine model 1 / (Je · s) is quickly used. Can follow the speed of the dynamometer 4 or the engine 1. As a result, the input of the engine speed to the vehicle model 6 becomes faster, approaches the actual engine speed, and a more appropriate engine test becomes possible.
[0020]
FIG. 4 is a Bode diagram for comparing the prior art shown in FIG. 5 with the present invention shown in FIG. 3, wherein a solid line A is the present invention and a chain line B is the conventional one.
In the engine test apparatus, whether or not the hunting phenomenon as shown in FIG. 6 occurs is not determined by the closed-loop characteristics of the shaft torque control system or the characteristics of the vehicle model unit alone. It can be understood that it is determined by a suitable combination of the two.
[0021]
That is, when focusing on the point of frequency F (phase-360) where the signal is fed back in the same phase in the phase characteristic in FIG. 4, the gain of the line B representing the related art exceeds 0 dB, but the gain of the line A representing the present invention is It is less than 0 dB.
This indicates that the velocity signal of the dynamometer 4 input to the vehicle model unit 6 increases in amplitude and diverges (unstable phenomenon) in the related art every time the dynamometer 4 goes around the closed loop including the vehicle model. I have.
On the other hand, in the present invention, it is shown that the amplitude becomes smaller (stable) every time the closed loop is performed.
[0022]
【The invention's effect】
As described above, according to the present invention, the speed signal of the engine or the dynamometer is not directly input to the vehicle model unit, but the engine model speed signal output by the engine moment of inertia model unit is input to the vehicle model unit. It is composed. As a result, the present invention improves the overall closed-loop characteristics including the vehicle model section, thereby improving control stability.
Further, by adding control based on the engine torque map, it is possible to cope with a delay in response of the vehicle model unit, thereby enabling more appropriate engine tests.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of the present invention.
FIG. 2 is a characteristic diagram for explanation, in which (a) is a torque diagram of a dynamometer and (b) is an engine speed diagram.
FIG. 3 is a configuration diagram showing an embodiment of the present invention.
FIG. 4 is a Bode diagram for explanation.
FIG. 5 is a configuration diagram of a conventional engine test apparatus.
FIG. 6 is a characteristic diagram for explanation, in which (a) is a torque diagram of a dynamometer and (b) is an engine speed diagram.
[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 11 ... Controller 12 ... Engine model part 20 ... Engine torque map

Claims (4)

The engine and the dynamometer are directly connected via the rotating shaft, the rotational speed signal of the engine or the dynamometer is detected and introduced into the vehicle model part, and the vehicle model part generates the engine load torque command value to control the torque. And a torque current command value is obtained by using the load torque command value introduced by the torque control unit, the detected shaft torque value, and the rotation speed signal, and via the inverter according to the torque current command value. Control the dynamometer by
An engine model unit that generates a model speed signal of the engine and outputs it to a vehicle model unit, and a controller that inputs a deviation between the model speed signal of the engine and the rotation speed signal and converts the deviation into a torque signal, The output signal of the controller and the load torque command value of the engine from the vehicle model unit are added and output to the engine model unit, and the engine model unit calculates the model speed signal of the engine. Control unit for engine test equipment. 2. The control device according to claim 1, wherein the engine model unit outputs an engine model speed signal calculated by 1 / (Je · s). 3.
Here, Je is the moment of inertia of the engine. 3. The control device according to claim 1, wherein the controller is a controller having an integral characteristic or a proportional characteristic. An engine torque map representing the relationship between the engine speed, throttle opening and engine torque characteristics prepared in advance and prepared is provided. Wherein the estimated value and the output value of the controller are added, and the added signal and the load torque command value of the engine are added and output to an engine model unit. 4. The control device of the engine test device according to any one of 1 to 3.

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