JP3136855B2 - Automatic engine inertia measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic engine inertia measuring method.

[0002]

2. Description of the Related Art It is difficult to theoretically determine the inertia of a complicated rotating body such as an engine because it contains many errors. For this reason, as shown in FIG. 2, the inertia of the engine is controlled by controlling the dynamometer by speed control with the ignition of the engine OFF with the dynamometer 2 connected to the engine 1 via the shaft torque meter 3 as shown in FIG. A constant acceleration / deceleration is performed, the detection value of the shaft torque meter 3 when the torque at the time of acceleration / deceleration is output stably is measured, a regression line y = ax + b is obtained by a least square method using a computer, and | a | Inertia (kgmS ² ) (see FIG. 4).

In the measurement, the acceleration / deceleration number pattern is measured, and data of 10% at the start and 5% at the end of acceleration / deceleration are excluded (see FIG. 6).

[0004]

As shown in FIG. 5, the shaft torque signal A from the shaft torque meter outputs a large amount of torque ripple from the engine so that a low-pass filter is inserted to remove the torque ripple. B is used.

However, when a low-pass filter is inserted, torque ripple can be removed, but the waveform of the shaft torque signal B during acceleration / deceleration is delayed by the low-pass filter from the waveform of the shaft torque signal A, so that the error of the engine inertia value increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to measure the engine inertia without being greatly affected by the engine torque ripple without using a low-pass filter. It is an object of the present invention to provide a method for automatic measurement of engine inertia which can be performed by a vehicle.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, an automatic engine inertia measuring method according to the present invention provides a method of automatically turning off an engine, performing a constant acceleration / deceleration by a dynamometer, and applying a torque of the dynamometer to a load cell. Detects and controls the drive / absorption of the engine by controlling the load cell of the dynamometer, detects the engine shaft torque by calculation from the torque and rotation speed detected by the load cell, and measures the engine inertia by calculation from the shaft torque and speed. Is what you do. Since the dynamometer is load cell controlled and the engine shaft torque is detected by calculation from the dynamometer torque and rotation speed detected by the load cell, the shaft torque can be detected without being affected by the engine torque ripple. Therefore, the measurement accuracy of the engine inertia is improved.

[0008]

An embodiment of the present invention will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes an engine with an ignition OFF,
Reference numeral 2 denotes a dynamometer that accelerates and decelerates the engine, 4 denotes a load cell that detects the torque of the dynamometer via a torque arm, 5 denotes a rotation detector that detects rotation of the dynamometer, and 6 denotes a torque set value Tset of the dynamometer.
And a torque control amplifier for amplifying the deviation between the torque detection value Tdet from the load cell 4 and the load cell control of the dynamometer 2.
, A differential amplifier for amplifying this acceleration signal and outputting a fixed inertia signal of the dynamometer, and 9 an amplifier for amplifying a difference between the torque detection value Tdet and the fixed inertial signal of the dynamometer. .

Reference numeral 10 denotes a dynamometer rotation / mechanical loss curve, and when a rotation detection signal N is input, a dynamometer mechanical loss torque signal T corresponding to the rotation speed is input.
And 11 is an amplifier that subtracts the mechanical loss torque signal T from the output of the amplifier 9 and outputs a temporary shaft torque detection signal equivalent to the engine shaft torque.

The torque detection signal detected by the load cell is hardly affected by the engine torque ripple unlike the shaft torque detection signal detected by the shaft torque meter.
The waveform of the provisional shaft torque detection signal output from the amplifier 11 is a waveform obtained by removing the engine torque ripple waveform from the shaft torque detection signal waveform (A in FIG. 5) by the shaft torque meter.

Reference numeral 12 denotes a stable portion (effective portion in FIG. 6) of the provisional shaft torque detection signal from the amplifier 11 and a rotation detection signal N.
It is a computer that takes in the engine inertia value by taking the least square method.

According to this embodiment, since the engine torque ripple hardly enters the temporary shaft torque signal, it is not necessary to use a filter for removing the engine torque ripple. For this reason, the portion where the shaft torque is stable at the time of constant acceleration / deceleration can be measured with less error in the engine inertia value.

[0013]

Since the present invention is configured as described above, the following effects can be obtained.

(1) Engine inertia can be measured without using a shaft torque meter.

(2) The engine torque ripple is less likely to appear in the dynamometer torque detection signal detected by the dynamometer load cell than the shaft torque detected by the shaft torque meter, eliminating the need for a low-pass filter.

(3) Since the low-pass filter is not used, the waveform of the provisional shaft torque detection signal does not have a delay, and a portion where the shaft torque at the time of constant acceleration / deceleration becomes stable increases. Therefore, the error of the engine inertia value is reduced and the accuracy is improved.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a bench of a conventional engine tester.

FIG. 3 is a time chart for explaining an engine inertia measuring method.

FIG. 4 is a graph showing a regression line.

FIG. 5 is a time chart illustrating a conventional shaft torque.

FIG. 6 is an explanatory diagram of valid data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Dynamometer 3 ... Shaft torque meter 4 ... Load cell 5 ... Rotation detector 6 ... Torque control amplifier 7 ... Differentiator 8 ... Fixed inertia output amplifier 9, 11 ... Subtraction amplifier 10 ... Dynamometer mechanical loss torque generation Table 12: Computer

Claims (1)

(57) [Claims] 1. A method for detecting a shaft torque of an engine and measuring an inertia of the engine by calculation from the shaft torque and a speed of the engine, wherein the torque of the dynamometer is supplied to a load cell. And controlling the dynamometer by drive / absorption control by controlling the load cell of the dynamometer and detecting the shaft torque by calculation from the torque and the rotation speed detected by the load cell. Measuring method.