JPH04331347A - Chassis dynamometer device - Google Patents

Abstract

PURPOSE:To enable a driving resistance on a road to be reproduced accurately by compensating for a tire loss based on a noncontactly measured surface temperature of a tire. CONSTITUTION:A tire 4 is mounted to a roller 1 and then quick-acting switches 13 and 14 are switched to a side A. A speed setter 15 sets a speed of the roller 1 and then a tire loss compensate 12 enters a detection output of a speed sensor 8 and a torque sensor 9 which are provided on the rotary axis 5 and a thermometer 10 which noncontactly measures a surface temperature of tire which is provided hear the roller 1 without any contact. The compensator 12 entered tire loss change characteristic according to a temperature of the tire as data and sets tire loss as a function of the speed and the temperature. A driving resistance setter 11 entered an output of the sensor 8 and sets driving resistance which is obtained from serpentine characteristics of an actual road. Then, a subtraction portion 17 subtracts an output of the compensator 12 from this set output, thus enabling the driving resistance to be reproduced accurately.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chassis dynamometer device.

0002

[Prior Art] When a car to be tested is mounted on the rollers of a chassis dynamometer device and run, there is tire loss (rolling resistance) due to tire deformation in addition to dynamometer loss, which is the mechanical loss of the device. I know I will. Therefore, in the past, the running resistance experienced by a car when driving on the road was measured using methods such as the coastdown method, boost pressure method, and shaft torque method, and the running resistance on the road was reproduced on a chassis dynamometer device. ing.

0003

[Problems to be Solved by the Invention] By the way, when a car is run on a chassis dynamometer device, the tires are deformed due to the rotation of the rollers, causing tire loss, but conventionally, this tire loss occurs only at the speed of the car. If the running resistance to be simulated is RL (V), then the force FPAU absorbed by the power absorption section directly connected to the roller is F
PAU=RL(V)-f(V)
...(1)
Since the tire loss that changes with time (tire surface temperature) during the test mode was ignored, it was not possible to accurately reproduce the running resistance on the road.

The present invention has been made with the above-mentioned considerations in mind, and its object is to provide a chassis dynamometer that can accurately reproduce running resistance on the road by accurately correcting tire loss. The purpose is to provide a meter device.

[0005]

[Means for Solving the Problems] In order to achieve the above object, a chassis dynamometer device according to the present invention measures the surface temperature of a tire of a test vehicle placed on a roller in a non-contact manner. Tire loss is compensated for based on the measured temperature.

[0006]

[Operation] In the chassis dynamometer device configured as described above, tire loss compensation is performed taking into account not only the speed but also the tire surface temperature, so tire loss compensation can be performed accurately. It is possible to accurately reproduce the running resistance of

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 schematically show the configuration of a chassis dynamometer device according to the present invention. In these figures, 1 is a roller consisting of a main roller 2 and an idle roller, which were used for testing. A tire 4 on the drive side of a car is mounted on the tire 4. Then, the rotating shaft 5 of the main roller 1
A power absorption unit 6 such as a generator is connected to the rotary shaft 5, and a flywheel 7, a speed sensor 8,
A torque sensor 9 is provided. Further, in the vicinity of the roller 1, for example, an infrared radiation thermometer 10 is provided for measuring the surface temperature of the tire 4 in a non-contact manner.

Reference numeral 11 denotes a running resistance setting device for setting a running resistance obtained from actual road coasting characteristics, and the detection output of the speed sensor 8 is inputted thereto. Here, actual road coasting characteristics are defined as accelerating a test vehicle to a certain speed (for example, 100 km/h) on the road, stopping the generation of driving force, and driving the vehicle using its own inertial energy. , refers to the characteristic that energy is gradually consumed by running resistance. Therefore, the running resistance obtained from this characteristic is a function of speed.

Reference numeral 12 denotes a tire loss corrector for setting tire loss, into which tire loss change characteristics due to tire temperature, which will be described later, are input as data, as well as the detection output of the speed sensor 8, the detection output of the torque sensor 9, and the thermometer 10.
The detection output is inputted. And 13
, 14 are switches that interlock with each other. When the intercept is switched to the A side, tire loss can be set in the tire loss compensator 12. When switched to the B side, the chassis dynamometer device can be set to a value equivalent to the running resistance on the actual road. It controls the generation of resistance.

A speed setting device 15 sets the speed of the roller 1 when the interlocking switches 13 and 14 are switched to the A side, and a comparison device 16 compares the detection output of the speed sensor 8 and the value set by the speed setting device 15. 17 is running resistance setting device 1
A subtraction unit 18 subtracts the output of the tire loss corrector 12 from the output of the subtraction unit 17, and a comparator 18 compares the output of the subtraction unit 17 with the detection output of the torque sensor 9. This comparator 18 constitutes a feedback system that controls the output of the subtractor 17 to be equal to the detection output of the torque sensor 9.

[0012] Now, to explain tire loss in the present invention, let fT (V) be the speed characteristic of tire loss at tire temperature T, and let AT, BT, CT be the coefficients of the approximation equation at temperature T. teeth,
fT (V)=AT +BT
V+CT V2
...It is expressed as (2).

[0013] Then, the values of each coefficient with respect to temperature T are determined, and the relationships between temperature T and each coefficient AT, BT, CT are obtained as shown in FIGS. 3(A), (B), and (C). , At this time, each of the coefficients AT , BT , CT is expressed as follows. AT =A0 +A1 T+A2 T2 +A
3 T3
...(3) BT =B0 +B1 T+B2
T2 +B3 T3
...(4) CT =C0 +C1
T+C2 T2 +C3 T3
...(5)

[0014] Therefore,
To express tire loss as a function of temperature T and speed V, f
If (T, V) is defined, f(T, V)=fT
(V)=AT +BT V+CT V2
=(A0 +A1 T+A2
T2 +A3 T3 )+(B0 +B1 T+
B2 T2 +B3
T3 )V+(C0 +C1 T+C2 T2 +
C3 T3 ) V2
=(A0 +B0
V+C0 V2 )+(A1 +B1 V+C1 V
2) T+(A
2 +B2 V+C2 V2 )T2 +(A3 +B
3 V+ C3
V2) T3
... is given by (6).

[0015] Changes in tire loss due to the surface temperature (initial temperature) of the tire 4 were investigated under the conditions described below. In other words, the car used in the test was 1800
ccFR car (ISET 1100Kgf), tires are
185/70R14 87H, tire pressure is 2.
0 Kg/cm2
Tire loss was measured using the ghost-down method by varying the initial surface temperature of the tire 4. Moreover, the room temperature was 20°C.

FIG. 4 is a characteristic diagram showing part of the results of the above test, where the horizontal axis represents vehicle speed (Km/h) and the vertical axis represents tire loss (Km/h).
(Loss force converted to the roller surface) is shown respectively. In this figure, curves (1) to (2) indicate the results obtained using a two-axis roller, and curves (2) to (2) indicate those obtained using a single-axis roller. In each of the curves ■ to ■, the initial temperature of the tire 4 is 22℃, 30℃, 40℃, respectively.
Cases of 50°C, 22°C, 30°C, 37°C, and 42°C are shown.

In the chassis dynamometer device configured as described above, the tires 4 of the automobile are mounted on the rollers 1, the running characteristics obtained from the coasting characteristics of the actual road are set in the running resistance setting device 11, and the interlocking switch 13 is set. , 14 to the B side, the force FPAU absorbed by the power absorption section directly connected to the roller 1 is: FPAU = RL (V) - f (T, V)
……
(7), and the running resistance on the road can be accurately reproduced.

In the above explanation, the loss (dynamo loss) of the dynamometer device is ignored, but if this cannot be ignored, then on the right side of the equation (7) above, if the dynamo loss is further subtracted, good.

Note that when performing a cold start test such as in the 11 mode or LA-4CT mode, the tire loss may vary greatly depending on the temperature of the tires 4, making it impossible to make accurate corrections. In this case, the change due to tire temperature may be added to the correction value when the vehicle is warmed up at a constant speed for a certain period of time.

[0020]

[Effects of the Invention] As explained above, according to the present invention,
Since tire loss compensation is performed by taking into account not only the speed but also the tire surface temperature, tire loss compensation can be performed accurately.Therefore, the running resistance on the road can be accurately reproduced, and the vehicle It is possible to conduct driving tests more accurately.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing an example of a chassis dynamometer device according to the present invention.

FIG. 2 is a diagram showing the configuration of a portion that measures the surface temperature of a tire.

[Figure 3] Figures 3 (A), (B), and (C) are each at a temperature T
It is a figure which shows the relationship between and each coefficient AT, BT, CT.

FIG. 4 is a characteristic diagram showing changes in tire loss depending on tire surface temperature.

[Explanation of symbols]

1...roller, 4...tire.

Claims (1)

[Claims] [Claim 1] A chassis dynamometer characterized in that the surface temperature of a tire of a test vehicle placed on a roller is measured in a non-contact manner, and tire loss is corrected based on the measured temperature. Device.