JP4591177B2 - Engine test equipment - Google Patents

Description

  The present invention relates to an engine test apparatus, and more particularly to a control apparatus that compensates for responsiveness of a torque control system of a dynamometer.

  FIG. 3 shows the configuration of the engine test apparatus. A dynamometer 4 is connected to the engine 1 via a shaft 2 and a shaft torque meter 3, and the dynamometer 4 is driven by an inverter 5. Reference numeral 6 denotes a vehicle model unit, which is composed of, for example, a four-inertia spring model and a vertical vibration model using a suspension and a tire spring. The detected dynamometer speed signal (or engine speed signal) is input to the engine load torque. A command (control point torque command) is output to the torque control unit 7.

  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 speed signal from the dynamometer 4, and sends the signal to the inverter 5. Output. The inverter 5 is subjected to torque current control so that the detected shaft torque signal follows the torque command value, thereby obtaining an engine load characteristic simulation operation.

  In the above configuration, the load torque actually applied to the engine 1 is delayed with respect to the load torque command value output from the vehicle model unit 6 due to the control delay of the torque control system of the control device. As a result, the engine speed is reduced. A hunting phenomenon may be caused and a highly accurate simulation operation may not be performed.

  As a method for compensating the response of the torque control system, the applicant of the present application has already proposed a control device having the configuration shown in FIG. 4 (see, for example, Patent Document 1). 3 differs from FIG. 3 in that the engine speed change is estimated (predicted) using an engine model or the like instead of the dynamometer or engine speed signal that is input to the vehicle model 6, and this is the vehicle model 6. The engine load torque is feedforward controlled by using the speed signal.

  In FIG. 4, the engine model unit 8 is set with the inertia moment Je of the engine as a constant, and the engine model is calculated by calculating {Te / (Je · s)} with respect to the differential torque Te between the engine output torque and the load torque by the dynamometer. The speed is obtained, and this engine model speed is set as the speed input of the vehicle model 6. Here, s is a Laplace operator.

  The engine torque map 9 has characteristics obtained by graphing the relationship between engine speed, throttle opening, and engine torque characteristics prepared in advance by measurement, and the detected dynamometer speed or engine speed and the throttle in the throttle actuator. The engine output torque is estimated from the opening signal. A differential torque Te obtained by adding the engine output torque and the engine load torque command of the vehicle model 6 (torque having a polarity opposite to the engine output torque) is given to the engine model unit 8.

  The controller 10 performs a proportional integral (PI) operation with a transfer function G (s) on the deviation between the engine model speed and the actual dynamometer speed, and corrects a torque error corresponding to the deviation. The torque error correction amount obtained by the controller 10 is added to or subtracted from the engine output torque obtained from the engine torque map 9 and included in the differential torque Te of the engine model unit 8 as a correction amount. The transfer function G (s) of the controller 10 has a characteristic that causes the model engine speed output from the engine model unit 8 to follow the actual engine speed or the dynamometer speed.

  The engine 1 is feedback-controlled by a throttle opening control circuit (not shown) so that there is no deviation between the throttle opening command and the detected throttle opening signal.

As a modification of the above method, Patent Document 1 also proposes a control method that does not use the engine torque map 9. In this case, the controller 10 obtains an output including the engine output torque.
JP 2004-177259 A

  In the conventional control device of FIG. 4, it is necessary to obtain the engine torque map 9 in advance before the engine test, that is, to measure the engine output torque characteristics using the engine under test.

  Further, since the engine torque map 9 is a measured value (average value) when the engine is in a constant speed state, it is difficult to match the estimated torque with the actual torque in a test including acceleration or deceleration in real time. When the transfer function G (s) of the controller 10 is not properly adjusted, the input engine speed to the vehicle model 6 becomes inappropriate, causing a problem that desired test accuracy cannot be obtained.

  Further, when the engine torque map 9 is not used, the measurement is not necessary. However, the transfer function G (s) of the controller 10 needs to be adjusted more appropriately than when the engine torque map is used, and the test accuracy is ensured. Becomes more difficult.

  An object of the present invention is to provide an engine test apparatus that can eliminate the need for an engine torque map, eliminate the need for a controller, or simplify the transfer function adjustment to increase the test accuracy.

  In order to solve the above problems, the present invention provides an engine torque observer for estimating an engine output torque from an axial torque, a dynamometer speed, and an engine inertia moment, and the engine output torque and an engine load torque command of a vehicle model section are The engine model speed is obtained from the differential torque and has the following configuration.

(1) The engine and the dynamometer are coupled via a rotating shaft, the vehicle model unit obtains an engine load torque command from the engine speed signal, and the torque control unit generates the load torque command and a shaft torque signal generated on the rotating shaft. And an engine test apparatus for controlling torque of the dynamometer based on a dynamometer speed signal,
Using the shaft torque T _tm and dynamometer speed ω _dy as inputs,
T _eg O = (J _eg · s (ω _dy ) −T _tm ) / Go (s)
However, J _eg is an engine moment of inertia, Go (s) is a transfer function in which 1 / Go (s) is a first-order or higher-order low-pass filter characteristic, and s is a Laplace operator.
An engine torque observer for estimating the engine output torque T _eg O by the calculation of
Using the engine output torque T _eg O and the engine load torque command T _eg L as inputs,
ω _eg M = {1 / (J _eg · s)} * (T _eg O−T _eg L)
The calculation of, determine the engine model speed omega _eg M, characterized by comprising an engine inertia model unit for inputting the engine model speed omega _eg M as an engine speed signal of the vehicle model unit.

(2) Using the engine model speed ω _eg M and the engine speed ω _dy as inputs,
T _eg M = G _m (s) * (ω _dy −ω _eg M)
Where G _m (s) is the transfer function of the proportional-integral characteristic,
The engine torque estimated value correction part T _eg M is obtained by the above calculation, and the engine torque estimated value correction part for adding the correction part T _eg M to the output of the observer is provided.

  As described above, according to the present invention, the engine torque observer is provided for estimating the engine output torque from the shaft torque, the dynamometer speed, and the engine moment of inertia, and the differential torque between the engine output torque and the engine load torque command of the vehicle model unit. Since the engine model speed is obtained from the conventional engine torque map, the conventional engine torque map becomes unnecessary. In addition, the observer can estimate the engine output torque in real time using the actual values of the shaft torque and the engine speed, and can increase the accuracy of the test including acceleration or deceleration.

  Also, because the estimated engine torque is corrected from the deviation between the engine model speed and the dynamometer speed (engine speed), it can be corrected even if the estimated value of the engine output torque contains an error for some reason. The test accuracy can be further increased by substantially matching the dynamometer speed (engine speed).

(Embodiment 1)
FIG. 1 is a configuration diagram of an engine test apparatus showing an embodiment of the present invention. 4 differs from FIG. 4 in that an engine torque observer 11 is provided in place of the engine torque map 9 and the controller 10.

The engine torque observer 11 receives the shaft torque detected by the shaft torque meter 3 and the dynamometer speed as inputs, and estimates the engine output torque T _eg O in real time by the calculation of the following equation (1).
[Equation 1]
T _eg O = (J _eg · s (ω _dy ) −T _tm ) / Go (s) (1)
However, J _eg is an inertia moment value on the engine side of the shaft torque meter 3, and is measured in advance as the engine inertia moment. Also, ω _dy is the dynamometer speed (or engine speed), T _tm is the shaft torque value detected by the shaft torque meter, Go (s) is a transfer function that has a low-pass filter characteristic with 1 / Go (s) being higher than the first order, s is a Laplace operator.

This calculation adds the torque amount {J _eg * s (ω _dy )} added to the moment of inertia on the engine side of the shaft torque meter 3 and the shaft torque value (the shaft torque becomes a negative value and is subtracted). ) To estimate the engine output torque T _eg O.

The engine inertia model unit 12 obtains the engine model speed ωegM by the calculation of the following formula (2).
[Equation 2]
ω _eg M = {1 / (J _eg · s)} * (T _eg O−T _eg L) (2)
However, T _eg L is an engine load torque command obtained for the vehicle model 6.

In this calculation, the engine model speed ω _eg M is obtained by calculating {1 / (J _eg · s)} with respect to the differential torque between the engine output torque T _eg O and the engine load torque command T _eg L.

From the above, in the present embodiment, the engine torque observer 11 estimates the engine output torque T _eg O from the shaft torque and the dynamometer speed (engine speed), so that the conventional engine torque map is not necessary.

  In addition, while the conventional engine torque map is a measured value (average value) when the engine is in a constant speed state, the engine output torque is estimated in real time using measured values of shaft torque and engine speed. The accuracy of the test including acceleration or deceleration can be increased by calculating the engine model speed using this. Further, correction by the controller is unnecessary.

(Embodiment 2)
FIG. 2 shows a configuration diagram of an engine test apparatus showing an embodiment of the present invention. 1 is different from FIG. 1 in that an engine torque estimated value correction unit 13 is added.

The estimated engine torque correction unit 13 performs a proportional integral (PI) operation with a transfer function Gm (s) on the deviation between the engine model speed obtained by the engine inertial model unit 12 and the actual dynamometer speed (engine speed). This is output as an engine torque estimated value correction. That is, the engine torque estimated value correction amount T _eg M is obtained by the following equation (3), and correction is performed so that ω _dy = ω _eg M.
[Equation 3]
T _eg M = Gm (s) * (ω _dy −ω _eg M) (3)
The output of the engine torque estimated value correction unit 13 is added to the engine torque T _eg O estimated by the engine torque observer 11. That is, the engine inertia model unit 12 calculates the engine model speed ω _eg M by the following equation (4).
[Equation 4]
ω _eg M = {1 / (J _eg · s)} * (T _eg O + T _eg M−T _eg L)
... (4)
Therefore, according to the present embodiment, in addition to the operational effects of the first embodiment, the estimated value of the engine output torque T _eg O is increased for some reason, such as when there is an error in the engine inertia moment value assumed by the observer 11. If an error is included, this can be corrected by the engine torque estimated value correction unit 13, and the engine model speed can be made to substantially match the actual dynamometer speed (engine speed), thereby further improving the test accuracy.

Further, the transfer function Gm (s) of the engine torque estimated value correction unit 13 can be expected to have a very small speed deviation (ω _dy −ω _eg M) due to accurate engine torque estimation by the observer. It only needs to be set and the adjustment becomes simple.

The block diagram of the engine test apparatus which shows Embodiment 1 of this invention. The block diagram of the engine test apparatus which shows Embodiment 2 of this invention. The block diagram of the conventional engine test apparatus. The block diagram of the other conventional engine test apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Coupling shaft 3 Axis torque meter 4 Dynamometer 5 Inverter 6 Vehicle model part 7 Torque control part 8 Engine model part 9 Engine torque map 10 Controller 11 Engine torque observer 12 Engine inertia model part 13 Engine torque estimated value correction part

Claims (2)

An engine and a dynamometer are coupled via a rotating shaft, a vehicle model unit obtains an engine load torque command from an engine speed signal, and a torque control unit detects the load torque command, a shaft torque signal generated on the rotating shaft, and a dynamometer In an engine test apparatus that performs torque control of the dynamometer based on a speed signal,
Using the shaft torque T _tm and dynamometer speed ω _dy as inputs,
T _eg O = (J _eg · s (ω _dy ) −T _tm ) / Go (s)
However, J _eg is an engine moment of inertia, Go (s) is a transfer function in which 1 / Go (s) is a first-order or higher-order low-pass filter characteristic, and s is a Laplace operator.
An engine torque observer for estimating the engine output torque T _eg O by the calculation of
Using the engine output torque T _eg O and the engine load torque command T _eg L as inputs,
ω _eg M = {1 / (J _eg · s)} * (T _eg O−T _eg L)
An engine test apparatus comprising: an engine inertia model unit that obtains an engine model speed ω _eg M by the calculation of and inputs the engine model speed ω _eg M as an engine speed signal of the vehicle model unit. Using the engine model speed ω _eg M and the engine speed ω _dy as inputs,
T _eg M = G _m (s) * (ω _dy −ω _eg M)
Where G _m (s) is the transfer function of the proportional-integral characteristic,
2. The engine according to claim 1, further comprising an engine torque estimated value correction unit that obtains an engine torque estimated value correction amount T _eg M by the calculation of and adds the correction amount T _eg M to the output of the observer. Test equipment.

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