JP3489241B2 - Automotive engine test equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile engine test apparatus. 2. Description of the Related Art In recent years, in view of the problem of environmental pollution, exhaust gas regulations on automobiles have become strict, and automobile engines have been improved in performance and accuracy. Accordingly, test devices for evaluating engine performance have come to play an important role. FIG. 4 shows a conventional engine test apparatus. In the drawing, reference numeral 1 denotes an engine, 2 denotes a dynamometer connected to the engine 1 via a propeller shaft 3, the dynamometer 2 is controlled by a voltage and a current from a dynamometer control unit 4, and the output of the dynamometer 2 is controlled. It is input to the operation panel 5. Further, the speed and the speed command value of the dynamometer 2 are inputted from the control operation panel 5 to the dynamometer control unit 4, and the speed and the torque value of the dynamometer 2 are inputted to the analog or digital PI control unit 6, and the PI control is performed. A position command value for driving a throttle actuator 7 for driving a throttle valve of the engine 1 is given to the driver 8 from the section 6, and a position signal is given to the driver 8 from the throttle actuator 7. [0003] In the engine test apparatus having the above configuration,
The performance of the engine 1 is evaluated by operating the speed or torque of the engine 1 in a predetermined pattern and measuring the exhaust gas, fuel consumption, and the like of the engine 1. At this time, since it is difficult to directly detect the torque of the engine 1, the output of the shaft torque of the propeller shaft 3 or the output of the dynamometer 2 directly connected to the engine 1 is input to the PI control unit 6. Thus, the engine 1 is controlled. As described above, in the above-described conventional vehicle engine test apparatus, when the torque of the engine 1 is controlled,
Because it is difficult to directly detect engine torque,
The shaft torque of the propeller shaft 3 or the torque of the dynamometer 2 is input to the PI control unit 6 through the control operation panel 5,
Although the PI controller 6 controls the engine torque to be the set value, the acceleration / deceleration torque of the dynamometer 2 interferes with the engine torque, that is, the engine torque control system and the speed control system of the dynamometer 2 interfere. , Engine torque control characteristics deteriorated. Accordingly, the present applicant has proposed to solve this problem by estimating the engine torque using an observer and feeding back the estimated torque.
FIG. 5 shows such an automobile engine test apparatus. In the figure, reference numeral 9 denotes an engine control system controlled object, which is a block diagram of the engine 1, the dynamometer 2, and the propeller shaft 3. Reference numeral 10 denotes a throttle actuator position control system, which includes a deviation device 10a, a P amplifier 10
b, deviation device 10c, PI amplifier 10d, current control unit (A
CR) 10e and a constant part (Km) 10f. The output of the position control system 10 takes deviations from various mechanical constants (Kc, Kd) 12 and 13 and a throttle valve spring coefficient (Kb) 11, and the deviation output is output from the engine inertia unit 14 and the engine inertia unit 14. The signal is input to the wire hysteresis unit 16 via the integration unit 15 (the output is the actuator position θm). The wire hysteresis unit 16 is configured by a wire connecting the actuator and the throttle valve. The throttle valve opening θA which is the output of the wire hysteresis unit 16
Is input to the engine characteristic unit 17, and the output thereof obtains the engine torque TE. The engine torque TE is input to a two-inertia model block 18 composed of a two-inertia system in which the engine 1 and the dynamometer 2 are directly connected. The two-inertia model block 18 includes the deviation unit 1
8a to 18c, engine inertia part 18d, spring coefficient part 18
e, and a dynamometer inertia unit 18f.
The engine torque TE and the spring coefficient portion 18 are provided in the deviation device 18a.
e, the shaft torque TP, which is the output of the engine inertia unit 1d, is supplied to the engine inertia unit 18d.
The engine speed NE is output from 8d. Deflector 18
The shaft torque TP and the dynamometer torque TLC are supplied to b, and the deviation output thereof is input to the dynamometer inertia unit 18f, and the dynamometer inertia unit 18f outputs the dynamometer speed ND. The engine speed NE and the dynamometer speed ND are supplied to the deviation device 18c, and the deviation output thereof is input to the spring coefficient section 18e, and the shaft torque TP is obtained from the output. The output equations of the model state of the two-inertia model block 18 are expressed by the following equations (1) and (2). [0008] Reference numeral 19 denotes a dynamometer speed control system.
A deviation device 19a for taking a deviation between the dynamometer speed command and the dynamometer speed ND, a PI amplifier 19b for amplifying the deviation, a current control portion 19c, a constant portion 19d, a deviation device 18b and a dynamometer inertia portion 18f. The constant section 19d outputs the dynamometer torque TLC. Reference numeral 20 denotes an engine torque control system, which is a deviator 21 for calculating a deviation between the engine torque command value and the estimated engine torque value by TE (hereinafter, the estimated value is indicated by ∧).
The PI controller 22 outputs the position command value of the actuator that drives the throttle valve of the engine 1, the dynamometer torque TLC and the dynamometer speed ND, and inputs the deviation to the estimated engine torque value.
Is output from the minimum dimension observer 23.
The parameters estimated by the minimum-dimensional observer unit 23 are the engine torque TE, the engine speed NE, and the shaft torque TP.
Expression. ## EQU2 ## The above equations (3) and (4) are converted to Gopinath
The observer was designed to be a triple root by a design method. The parameters A to D and G at that time are as follows. [0013] FIG. 6 shows a block configuration of the minimum dimension observer unit 23. The dynamometer torque TLC is supplied to an adder 23a via a parameter B, and the dynamometer speed ND is given to the adder 23a via a parameter G. And the output of parameter A is provided. The output of the adder 23a is provided to the integrator 23b, and the output is provided to the adder 23c via the parameter C and also to the parameter A. Also, the adder 23c
Is supplied with a dynamometer speed ND via a parameter D, and the adder 23c outputs an estimated engine torque value ∧TE. In the above configuration, the engine torque control system 20 is opened, and the dynamometer 2 is
When the speed is controlled to 0 rpm and the position command of the throttle actuator is stepped up by 20%, the dynamometer torque TLC is added with the acceleration / deceleration torque due to the speed control system, but the engine estimated torque has an estimated delay with respect to the intake pressure. However, they almost coincide with each other, coincide with the actual engine torque, and are not affected by the dynamometer control system. As described above, by using the estimated engine torque value, the interference of the dynamometer speed control system 19 can be eliminated and the engine torque control can be stably performed. As described above, in the conventional automobile engine test apparatus, the engine torque is controlled by adjusting the opening θA of the throttle valve of the engine 1. Since it is difficult to directly detect the opening position, the position θm of the actuator connected to the throttle valve is detected and fed back to adjust the throttle valve opening θA. However, the throttle valve and the actuator are connected by a wire, have a hysteresis characteristic in the control system as shown by a wire hysteresis section 16, and cause friction between the wire and the contact section. Also, Engine 1
The dead time from the intake to the combustion of the engine occurred, and these non-linear factors adversely affected the engine torque control characteristics. For example, as shown in FIG.
When the engine torque command value is changed from 4% to 8% while the engine speed NE is controlled to 2000 rpm according to 9, a continuous vibration of about 1% occurs in the actuator position command, the intake pressure, and the estimated engine torque ∧TE. did. This is because the gain margin of the PI control system becomes small due to gain fluctuation and phase delay due to hysteresis and phase delay due to dead time, and the state becomes unstable depending on the state. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and suppresses torque fluctuations in an engine torque control system due to interference of a dynamometer speed control system, and also provides a throttle valve for an engine and its actuator. It is an object of the present invention to obtain an automobile engine test apparatus capable of suppressing the instability of an engine torque control system due to hysteresis of a wire connecting the motor and dead time of engine characteristics. An automobile engine control apparatus according to the present invention receives an actuator position control system, a dynamometer speed control system, a torque and a speed of a dynamometer, and calculates an estimated engine torque value. Modeling the minimum dimension observer section to be output, the control object until the torque estimation value is obtained from the actuator position command, an internal model consisting of the third-order delay and dead time excluding the hysteresis characteristics, and the engine torque estimation value A first controller for compensating for a modeling error or a disturbance error, and an engine torque command value and a first controller.
When the deviation from the output of the controller is input, the engine torque response becomes the target response when the internal model and the control target coincide, and the output becomes the position command value of the actuator position control system. And a second controller which is input to the internal model. According to the present invention, an estimated engine torque value is obtained, and the engine torque is controlled based on the estimated value, so that the dynamometer speed control system does not interfere. or,
The control object until the torque estimation value is obtained is modeled except for the hysteresis characteristic to form an internal model, and the second controller determines that the engine torque has a target response when the internal model matches the control object. The first controller compensates for modeling errors and disturbance errors. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an automobile engine test apparatus according to this embodiment. Reference numeral 24 denotes an estimated engine torque from a minimum dimension observer unit 23 and an internal model 25 (P).
M (S)) and a deviation controller 26 for obtaining a deviation from the output of the first controller (C2) to which the output of the deviation device 24 is input.
(S)) and 27 are a deviation device which receives the engine torque command value and the output of the first controller 26 and outputs the deviation thereof.
8 is a second controller (C1) to which the output of the deviation unit 27 is input.
(S)). Here, by approximating from the engine torque to the estimation with a first-order lag, the controlled object from the actuator position command to the estimated torque value, that is, the controlled object 9 and the minimum dimension observer 23 are modeled as shown in FIG. Can be 29 and 31 are first-order lag elements, and 30
Is a first-order lag / dead time element. Of these, since the wire hysteresis unit 16 cannot be modeled in practice, the internal model 25 is constructed from the third-order delay element and the dead time element except for this, and the IMC (InternalMod) is used.
e Control) method is applied. In the IMC method, an internal model 25 to be controlled is provided in the system, and controllers 25 and 28 are provided, thereby constituting a two-degree-of-freedom control system. The transfer function P to be controlled of the internal model 25
M (S) is as shown in Equation 4. (Equation 4) When the transfer function PM (S) of the internal model 25 and the transfer function P (S) of the actual control object match, the second controller 28 changes the engine torque response to the target response transfer function R (S). It is constituted so that it may become. That is, the configuration is as shown in Expression 5. C1 (S) is the transfer function of the second controller 28. (Equation 5) Therefore, C1 (S) becomes as shown in Expression 6. [Equation 6] The first controller 26 is for compensating for disturbances and modeling errors, and its transfer function C2 (S) reduces the gain in the low frequency region in consideration of the disturbance characteristics.
The engine torque command value and the estimated engine torque value are configured to be equal in a steady state at the time of a disturbance input. (Equation 7) Therefore, C2 (S) becomes as shown in Expression 8. (Equation 8) In the above configuration, the deviation unit 24 estimates the torque value from the minimum dimension observer unit 23 and the internal model 25
Is obtained, and the first controller 26 receives the deviation and compensates for the error. The deviation device 27 calculates the deviation between the engine torque command value and the output of the first controller 26,
This deviation is input to a second controller 28, and the second controller 28 generates an output such that the engine torque response becomes a target response when the internal model 25 and the above-mentioned controlled object coincide with each other. It is inputted as a position command value to the actuator position control system 10 and also inputted to the internal model 25. In the above embodiment, the engine torque is estimated by the minimum dimension observer 23, and the engine torque is controlled based on the estimated engine torque. The fluctuation of the engine torque control system due to the interference of the dynamometer speed control system 19 is performed. Was suppressed. Also, I
Applying the MC method, the internal model 25 and the controllers 26 and 28
Is provided, it is possible to eliminate the instability of the engine torque control system due to the influence of the hysteresis characteristic of the wire and the dead time of the engine. For example, as shown in FIG. 3, the dynamo speed control system 19 controls the engine speed NE.
When the engine torque command value was changed from 4% to 8% in a stepwise manner while controlling the engine torque to 2000 rpm, no vibration occurred in the actuator position command value, the intake pressure, and the estimated engine torque value. As described above, according to the present invention, the engine torque is controlled based on the estimated value of the engine torque, and the interference of the dynamometer speed control system is eliminated to reduce the fluctuation of the engine torque control system. Can be suppressed. Also, by applying the IMC method to the engine torque control system,
Instability of the engine torque control system due to wire hysteresis and dead time of the engine can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an automobile engine test apparatus according to the present invention. FIG. 2 is a diagram modeling a control target according to the present invention; FIG. 3 is an operation waveform diagram of each part of the automobile engine test apparatus according to the present invention. FIG. 4 is a block diagram of a conventional device. FIG. 5 is a block diagram of an automobile engine test apparatus proposed by the present applicant. FIG. 6 is a block diagram of a minimum dimension observer unit proposed by the present applicant. FIG. 7 is an operation waveform diagram of the applicant's proposed device. [Description of Signs] 1 ... Engine 2 ... Dynamometer 3 ... Peller shaft 7 ... Actuator 9 ... Control target unit 10 ... Actuator position control system 16 ... Wire hysteresis unit 19 ... Dynamometer speed control system 20 ... Engine torque control system 23 ... Minimum dimension observer unit 25 Internal model 26 First controller 28 Second controller

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01M 15/00-17/007 G01L 3/16 G05B 23/00-23/02 302

Claims (1)

(1) An automobile engine test apparatus for performing an engine test by connecting a dynamometer to an automobile engine and connecting an actuator to a throttle valve of the engine via a wire. An actuator position control system for controlling the position, a dynamometer speed control system for controlling the speed of the dynamometer, a minimum dimensional observer section for inputting the torque and speed of the dynamometer and outputting an estimated engine torque, and an actuator position command The model to be controlled until a torque estimate is obtained from the model is input, and the deviation between the engine model estimated value and the output of the internal model, which is composed of the third order delay and dead time excluding the hysteresis characteristic, is input. A first controller for compensating for modeling errors and disturbance errors; With the deviation between the output of Ntoruku command value and the first controller is input, the engine torque response is configured to be target response when the internal model and the said controlled object coincide with each other,
An automobile engine test apparatus comprising: a second controller whose output is a position command value of an actuator position control system and is input to an internal model.