JP2003130751A - Testing equipment for car parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that highly accurate and responsive control is difficult because a temperature drift is generated in a torque meter when a dynamometer is controlled by the detection of the torque of a torque meter. SOLUTION: The temperature of the torque meter 8 is detected other than the torque detection signal from the torque meter 8. A temperature drift map preliminarily measuring the temperature drift characteristics of the torque meter is prepared in an engine torque correction part 13 and the torque detection value due to the temperature drift is corrected. Further, a table preliminarily measuring temperature-rated torque characteristics is prepared and the torque detection value is corrected on the basis of the ratio of the temperature-rated torque characteristics to obtain the torque detection signal to a controller.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an apparatus for testing automobile parts using a dynamometer, and more particularly to torque control by detecting engine torque. 2. Description of the Related Art In an apparatus for testing automobile parts such as an engine, a transmission and a differential gear using a dynamometer, an engine bench system and a dynamometer driven by a combination of an engine drive and a dynamometer absorption system are known. And a power train bench composed of a dynamo absorption system. FIG. 6 shows an engine bench system in which an engine 1 and a transmission 2 are combined (AT or MT, with a clutch in the case of MT) and connected to a dynamometer 4 via a shaft 3. The output of the engine 1 is controlled by controlling the throttle opening by a throttle actuator 5.
The dynamometer 4 is provided with a rotation detector 6 and a torque detector (load cell) 7, and controls the speed and torque by feeding back these detection signals. This engine bench system enables tests such as engine durability and performance tests (fuel consumption, exhaust gas measurement, etc.) and ECU compatibility. In such an engine bench system,
In some cases, the resonance point of the machine is so low that high-response torque cannot be propagated from the dynamometer side to the engine side, or high-response behavior of the engine side cannot be propagated to the dynamometer side. In this case, the completed vehicle has to be used for the transient performance test of the engine and the vehicle-related parts. As a method of solving such a problem, recently, as shown in FIG. 7, the engine 1 and the dynamometer 4 are directly connected by a high steel shaft 3A, and the dynamometer has a high frequency characteristic with respect to the engine. A system has been proposed which enables torque propagation, reproduces transient performance close to that of a real vehicle, and enables an engine test without a vehicle. In the engine bench system, in the configuration shown in FIG. 7, torque propagation is obtained on the engine side with a high frequency characteristic, and the propagation torque is detected and controlled in accordance with the high frequency characteristic. It is hoped that it can be implemented. In this case, a high-response torque meter 8 is often provided on the engine 1 side as the torque detecting means. In this high-response torque meter, as shown in FIG. 3, there is a case where a temperature drift occurs. In this case, a detected value of the torque meter fluctuates due to a change in ambient temperature, and a large value included in the detected value. The error reduces the control accuracy of the shaft torque, and is a factor that hinders high-accuracy shaft torque control. Japanese Patent Application Laid-Open No. 61-129532 and Japanese Patent Application Laid-Open No.
243921 and Japanese Patent No. 3110260. In Japanese Patent Application Laid-Open No. 61-129532, a load cell and a temperature sensor signal are sequentially input by a switch, and the load cell detection signal is digitally corrected according to the temperature. However, in this method, since the input timing of the load cell output value and the sensor output value is shifted,
Cannot perform accurate temperature compensation. Further, in this system, means for calculating and correcting a conversion coefficient from a zero output point at an appropriate temperature and a span output is disclosed. In this case, since it is assumed that the load cell output value changes linearly between the measured temperatures, accurate temperature correction cannot be performed. In Japanese Patent Application Laid-Open No. 2-243921, a conversion coefficient is obtained from a reference temperature and a reference detection weight of the load cell at other temperatures. However, this method is based on the assumption that the load cell output value changes linearly between temperatures, as in the above-described method, so that accurate temperature correction cannot be performed. [0011] In Japanese Patent No. 3110260, the change characteristic of the oscillation frequency with respect to the temperature of the quartz oscillator is used.
It captures temperature information and compensates for temperature. Here, the torque detection timing is defined as 50 ms, and the torque detection value obtained by the moving average during the 25 ms period is defined as:
The correction is made based on temperature information from the oscillation frequency obtained by the moving average of the crystal oscillator clock during the 25 ms period during the same period. Although this method can measure the temperature accurately, it cannot be used for high-response torque control that requires high-speed torque detection. An object of the present invention is to provide a test apparatus for an automobile part which accurately corrects a detection error due to a temperature of a torque meter and enables high-response torque control. [0013] In order to solve the above-mentioned problems, the present invention prepares a map and a table in which a temperature drift characteristic and a temperature-rated torque characteristic of a torque meter are measured in advance. By extracting the current temperature drift included in the torque detection signal and the ratio of the temperature-rated torque characteristic based on the characteristics and the current temperature of the torque meter and correcting the torque detection signal, accurate and high-speed It is designed to perform temperature-compensated torque control and is characterized by the following configuration. In a test apparatus for an automobile part for driving an automobile part and controlling a dynamometer based on a torque detection signal of the torque meter, a temperature detector for detecting the temperature of the torque meter, and a temperature drift of the torque meter A characteristic is measured in advance, and a temperature drift map in which the torque due to the temperature drift is recorded and a differential torque between the zero torque and the rated load torque at each temperature of the torque meter are measured in advance and recorded as the rated torque corresponding to the temperature. A temperature-torque correction table to be determined, a torque A corrected by a current temperature drift from the temperature detected by the temperature detector and the temperature drift map, and a temperature A detected from the temperature detector and the temperature-torque correction table. The torque A is supplemented by a ratio B between the differential torque and the rated torque at the reference temperature. Characterized in that a temperature correction block. FIG. 1 is a control system configuration diagram of a test apparatus showing an embodiment of the present invention. As in FIG. 7, the engine 1 has a dynamometer 4 with a high steel shaft 3A.
To allow the dynamometer 4 to transmit torque to the engine 1 with high frequency characteristics. Also,
A high-response torque meter 8 is provided on the engine 1 side as torque detection means for detecting a propagation torque having a high frequency characteristic between the engine 1 and the torque meter 4. The controller 11 has a software configuration or a hardware configuration using a microprocessor, and calculates a proportional integral (PI) of a deviation between a shaft torque detected by the shaft torque meter 8 and a shaft torque command. Is obtained as a torque command for the dynamometer 4. The inverter 12 obtains an AC voltage output according to the torque command from the controller 11, and obtains an AC voltage having a frequency corresponding to the power absorption speed of the dynamometer 4. The dynamometer 4 is driven at a speed and an absorption torque according to the output of the inverter 12, and obtains a high-response torque transmission with the engine 1 via the shaft 3A. When the dynamometer 4 is constituted by a DC machine, a DC power control device such as a thyristor Leonard is used instead of the inverter 12. Here, in the present embodiment, a shaft torque correction unit 13 for correcting the temperature of the shaft torque is provided for taking in the detected shaft torque value from the shaft torque meter 8. The shaft torque correction unit 13 receives the detected torque signal and the temperature detection signal of the shaft torque meter 8, corrects the detected torque signal based on the temperature drift characteristic of the torque meter 8 and the temperature-rated torque characteristic, Is corrected by the change in the shaft torque. FIG. 2 shows a specific configuration diagram of the shaft torque correction unit 13. Since the shaft torque detection signal detected by the torque meter 8 includes a noise component in addition to a high frequency component for detecting a high response, the noise component is removed by the smoothing filter 14. The temperature drift map 15 records temperature drift characteristics of the torque meter 8 as a map. This temperature drift characteristic is measured in advance. For example, as shown in FIG. 3, it is assumed that the temperature and the torque output value under no load (zero torque) in the operating temperature range of the torque meter are measured in advance. The temperature-torque correction table 16 has, as data, rated torques at no load (zero torque) and at a rated load (rated torque) at each temperature. For example, as shown in FIG. Differential torque (rated torque) measured value Tref and each temperature T
It is assumed that the differential torques T1 to Tn at no load and at the rated load in EMP1 to TEMPn are picked up. The temperature correction block 17 includes the smoothing filter 1
4 from the torque detection signal passed through
5 and the temperature-torque correction table 16 is used to correct the temperature by the correction calculation of the shaft torque to obtain the final corrected shaft torque detection value. FIG. 5 shows a flow of temperature correction by the temperature correction block 17. First, the shaft torque detection signal Tdet
(S1), the temperature drift map value ΔT at that time is obtained in the temperature drift map 15 based on the temperature detection value of the torque meter (S2), and the temperature drift map value is subtracted from the shaft torque detection value to obtain the temperature. A torque value A from which the influence of the drift is removed is obtained (S3). A = torque meter output Tdet-temperature drift map value ΔT Next, a correction coefficient B is calculated based on the detected temperature value of the torque meter and the torque value of the temperature-torque correction table 16 (S4). ). The calculation of the correction coefficient B is based on the reference temperature TEMP.
ref and the current temperature TE
It is determined by the ratio of the differential torque Tm at MPm, that is, by the calculation of the following equation. B = Tm / Tref Next, a temperature corrected shaft torque is calculated by multiplying the torque output A corrected for the temperature drift by a correction coefficient B (S5). Obtain shaft torque output (S
6). Therefore, the shaft torque correction section 13 can correct the temperature drift with high accuracy by correcting the detected value of the torque meter with the temperature drift at that time.
Further, since the torque is corrected based on the variation of the span between the zero torque and the rated torque at each temperature of the torque meter, accurate temperature correction can be performed even when the temperature characteristics of the torque meter are not linear. In addition, since these corrections are made into a map and a table, high-speed processing can be performed with a simple calculation from the detection of the torque meter and the detected temperature value at that time, and high-response shaft torque control can be performed. Each unit of the shaft torque correction unit 13 can be realized by a digital operation element or an analog operation element.
Also, the calculation function of the shaft torque correction unit 13 is
1 can be realized as a software configuration of a microprocessor mounted therein. In the embodiment, the case where the torque control is performed by detecting the shaft torque is shown. However, the same operation and effect as the torque detection by the load cell can be obtained. Although the embodiment is applied to an engine bench system, the same operation and effect can be obtained by applying to an apparatus for testing a high response torque of an automobile part such as a transmission and a differential gear. . As described above, according to the present invention, the temperature drift characteristic and the temperature-rated torque characteristic of the torque meter are prepared as a map and a table in which the characteristics are measured in advance. Since the current temperature drift and the ratio of the rated torque characteristic included in the torque detection signal are extracted based on the temperature and the torque detection signal is corrected, the detection error due to the temperature of the torque meter can be accurately corrected, Moreover, high-response torque control is possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a control system configuration diagram of a test apparatus showing an embodiment of the present invention. FIG. 2 is a configuration diagram of a shaft torque correction unit in the embodiment. FIG. 3 is a temperature drift characteristic map of a torque meter. FIG. 4 is an example of a temperature-torque correction table in the embodiment. FIG. 5 is a processing flow of a temperature correction block in the embodiment. FIG. 6 is a configuration diagram of a conventional engine bench system (part 1). FIG. 7 is a configuration diagram (part 2) of a conventional engine bench system. [Description of Signs] 1 ... Engine 2 ... Transmission 3 ... Shaft 4 ... Dynamometer 8 ... Torque meter 11 ... Controller 12 ... Inverter 13 ... Shaft torque correction unit 14 ... Smoothing filter 15 ... Temperature drift map 16 ... Temperature-torque correction table 17… Temperature correction block

Claims (1)

Claims 1. An apparatus for testing an automobile part which drives an automobile part and controls a dynamometer based on a torque detection signal of a torque meter, wherein a temperature detector for detecting a temperature of the torque meter The temperature drift characteristic of the torque meter is measured in advance, and a temperature difference between the zero torque and the rated load torque at each temperature of the torque meter and a temperature drift map recorded as a torque component due to the temperature drift is measured in advance. A temperature-torque correction table recorded as a rated torque corresponding to the temperature, a torque A corrected by the current temperature drift from the temperature detected by the temperature detector and the temperature drift map,
A temperature correction block for correcting the torque A at a ratio B between the difference torque and the rated torque at a reference temperature from the temperature detected by the temperature detector and the temperature-torque correction table. Testing equipment.