JP2005265417A - Control method of dynamometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein the measurements of exhaust gases and fuel consumption is adversely affected by the idle running of a road roller, when a tire is pressed to the side of a free roller at deceleration and then the occurrence of errors in distance, based on a pattern between time-vehicle speed at vehicle tests which use a twin-roller-type chassis dynamometer. <P>SOLUTION: Running resistance F is provided by A+BV<SP>2</SP>+(1+dV/dt)×Wcosθ<SB>1</SB>+Wcosθ<SB>2</SB>at acceleration and is switched to a value determined by A+BV<SP>2</SP>+Wcosθ<SB>1</SB>+(1+dV/dt)×Wcosθ<SB>2</SB>(where A is rolling resistance; B is windage loss; V is vehicle speed; cosθ<SB>1</SB>=(√(R+r1)<SP>2</SP>-L1<SP>2</SP>)/(R+r1); cosθ<SB>2</SB>=(√(R+r2)<SP>2</SP>-L2<SP>2</SP>)/(R+r2); and W is mass of a vehicle). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for controlling a dynamometer, and more particularly to running resistance of a twin roller chassis dynamometer.

  One of the roller systems in the chassis dynamometer is the twin roller system. As shown in FIG. 3, this twin roller type chassis dynamometer has a twin roller of a road roller Rr and a free roller Rr for placing a tire T of a vehicle under test. Although not shown, a dynamometer is connected via a flywheel. The dynamometer is controlled by a control device such as an inverter.

  FIG. 3 shows only one tire, and the twin roller chassis dynamometer is configured such that the drive wheels or all tires are placed on the twin rollers as shown in FIG.

In the twin roller type chassis dynamometer, only the load roller Rr is connected to the dynamometer to set a load. As this load setting, the vehicle test is performed by setting the running resistance of the same value as the road running state on the road roller side and the dynamometer in the absorbing state while appropriately setting the friction coefficient between the tire T and the road roller Rr. . The running resistance F at that time is given by F = A + BV ² + WdV / dt.
Here, A is the rolling resistance of the vehicle, B is the windage loss of the vehicle under test, W is the mass of the vehicle under test, and dV / dt is the acceleration / deceleration.

As a twin roller type chassis dynamometer, one disclosed in Patent Document 1 is known.
JP 2002-148149 A

  FIG. 4 shows an aspect of acceleration and deceleration with a twin roller type chassis dynamometer. At the time of acceleration shown in (a) of the figure, the tire T is pressed against the road roller Rr side, but at the time of deceleration shown in (b), the tire T is pressed against the free roller Rf side. For this reason, the load roller Rr is idled to some extent.

  As described above, since the load is set on the road roller Rr, even if a signal accompanying the standard time-vehicle speed pattern is given from the vehicle, the distance does not become the travel distance calculated in advance from the time-vehicle speed due to the idling phenomenon. It becomes an error. That is, a phenomenon occurs in which the distance error is small at the time of acceleration but increases at the time of deceleration, and this distance error has a problem of greatly affecting exhaust gas and fuel consumption measurement.

  The present invention has been made in view of such points, and an object of the present invention is to provide a control method for following the load set value even during acceleration and deceleration.

A first aspect of the present invention is a chassis dynamometer in which a vehicle tire is mounted on a twin roller composed of a road roller and a free roller, and a vehicle test is performed based on a time-vehicle speed pattern signal using a dynamometer as a power absorber. ,
The vehicle tire radius is R, the road roller and free roller radii are r1 and r2, respectively, and the horizontal distance from the tire center point to the road roller center point and from the tire center point to the free roller center point is L1, respectively. When L2, the load setting traveling resistance F applied to the road roller is obtained by F = A + BV ² + (1 + dV / dt) × W cos θ ₁ + W cos θ ₂ when the vehicle is accelerated, and the vehicle is decelerated. In some cases, a value obtained by F = A + BV ² + W cos θ ₁ + (1 + dV / dt) × W cos θ ₂ is given.
Where A: rolling resistance of the vehicle, B: windage loss of the vehicle, V: detected vehicle speed, cos θ ₁ = (√ (R + r1) ² −L1 ² ) / (R + r1), cos θ ₂ =
(√ (R + r2) ² −L2 ² ) / (R + r2), W: vehicle mass, dV / dt: acceleration / deceleration.

  A second aspect of the present invention is characterized in that the judgment of switching of the running resistance at the time of acceleration and deceleration is performed with a waveform obtained by differentiating the detected vehicle speed signal. The present invention relates to.

  As described above, according to the present invention, when measuring the exhaust gas and fuel consumption of a vehicle with a twin roller chassis dynamometer, the load setting value following the acceleration and deceleration of the test standard pattern is set in advance, so that the time-vehicle speed Thus, no error occurs in the distance calculated from the above, and highly accurate measurement values can be obtained.

FIG. 2 is an explanatory view showing an embodiment of the present invention, in which only one wheel is displayed as a representative.
The radius of the tire T is R, the radius of the road roller Rr is r1, the radius of the free roller Rf is r2, and the horizontal distance from the center point of the tire to the center point of the road roller Rr is L1, free from the center point of the tire. Let L2 be the horizontal distance to the center point of the roller Rf.

In the present invention, in the equipment state shown in FIG. 2, the driving resistance F is switched to Formula 1 during acceleration and switched to Formula 2 during deceleration.
^{F = A + BV 2 + (} 1 + dV / dt) × Wcosθ 1 + Wcosθ 2 ...... 1 expression ^{F = A + BV 2 + Wcosθ} 1 + (1 + dV / dt) × Wcosθ 2 ...... 2 expression, _{however, cosθ 1 = (√ (R} + r1) 2 - L1 ² ) / (R + r1), cos θ ₂ =
(√ (R + r2) ² −L2 ² ) / (R + r2), W: vehicle mass.

  FIG. 1 is a control block diagram for running resistance calculation for realizing the above switching. In this control block diagram, only the portion related to the present invention is displayed, and the electric inertia part etc. originally possessed by the chassis dynamometer, etc. Various signal creation portions for torque calculation are omitted.

  In FIG. 1, reference numeral 1 denotes a control device including an inverter, 2 denotes a chassis dynamometer, and each tire of the vehicle is configured to be placed on a road roller Rr and a free roller Rf as shown in FIG. The load roller Rr is a twin roller type in which a load is set by being connected to a dynamometer. Reference numeral 3 denotes a vehicle speed detection means such as a pulse pickup, which converts the detected speed pulse into a voltage signal and outputs it as a speed signal V.

4 differentiates the velocity signal input by the differentiating circuit and outputs a (1 + dV / dt) signal to the multipliers 5 and 9, respectively. The multiplier 5, multiplies the signal with a known vehicle mass W and the cos [theta] ₁ are applied as set value, the output by the multiplier 5 is calculation of (1 + dV / dt) × Wcosθ 1 being performed adding unit 6 is applied. In the adder 6, the preset Wcos θ ₂ and (1 + dV / dt) × Wcos θ ₁ are added, and the output is applied to the adder 11.

Reference numeral 7 denotes a squaring circuit that squares the speed signal V, and its output V ² is applied to the multiplier 8 to perform multiplication with the windage loss setting signal B of the vehicle under test. The multiplication signal BV ² is added to the set value A of the rolling resistance of the vehicle in the adding unit 10 and output to the adding unit 11. The adder 11 performs addition with the output signal from the adder 6 to obtain A + BV ² + (1 + dV / dt) × W cos θ ₁ + W cos θ ₂ . That is, the running resistance according to the equation 1 is output from the adder 11.

On the other hand, the multiplier 9 calculates the set Wcos θ ₂ and (1 + dV / dt), and the adder 12 adds A + BV ² and Wcos θ ₁ and outputs the result to the adder 13. In the adder 13, A + BV ² + W cos θ ₁ from the adder 12 and (1 + dV / dt) × W cos θ ₂ from the multiplier 9 are executed, and A + BV ² + W cos θ ₁ + (1 + dV / dt) × W cos θ ₂ is obtained. can get.
That is, the running resistance F according to the two formulas is output from the adder 13.

14 is a switching means for switching to the terminal a or b side according to acceleration or deceleration. Here, the terminal a side is accelerated and the b side is decelerated. The switching command is obtained by differentiating the vehicle speed signal, for example. Whether to accelerate or decelerate is determined based on the positive and negative polarities. Reference numeral 15 denotes a torque control unit. In addition to the calculated running resistance, a signal required for torque calculation is input to the torque control unit, the control signal is calculated, and an inverter control signal is generated.

  A vehicle under test placed on a chassis dynamometer as a power absorber is driven based on a predetermined pattern of vehicle speed and time, and the vehicle speed is detected by the speed detection means 3. The differentiation circuit 4 differentiates the input speed signal and outputs it to the multipliers 5 and 9, respectively. The determination means 16 determines whether the vehicle is accelerating or decelerating on the basis of the differential signal, and performs switching. It outputs to the means 14 as a switching command.

  Therefore, when the vehicle under test is accelerating, the switching means 14 is connected to the terminal a side, and the torque control unit 15 is input with the running resistance value based on the equation 1, and the torque calculation is performed. After being converted to a signal, it is output to the inverter 1. The inverter controls the chassis dynamometer 2 by its output, and this dynamometer gives it to the load roller Rr as a load set value simulating a road running state via a flywheel or directly. The load setting value based on this formula 1 is a load setting value that is followed during acceleration of the test standard pattern time-vehicle speed.

  Next, when the vehicle under test changes to deceleration, a change command is issued to catch the change and switch to the terminal b side with respect to the switching means 14, and the torque control unit 15 is divided into two types. The running resistance value based on this is input, and the same is applied to the load roller Rr as a load set value in the same manner. The load set value based on Formula 2 is a load set value that follows deceleration in the test standard pattern time-vehicle speed.

  That is, since the load setting values follow the acceleration and deceleration based on the standard pattern during the vehicle test, the logical distance calculated from the standard pattern time-vehicle speed matches the actual test distance. Therefore, the measured exhaust gas and fuel consumption can be measured with high accuracy.

The control block diagram of running resistance which shows the embodiment of the present invention. FIG. 2 is a partial view of a twin roller for explaining the principle of the present invention. Partial view of the twin roller. It is explanatory drawing under test, (a) State figure at the time of acceleration, (b) State figure at the time of deceleration. Embodiment of this invention is shown

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Control apparatus 2 ... Twin roller type chassis dynamometer 3 ... Speed detection means 4 ... Differentiation circuit 5, 8, 9 ... Multiplier 7 ... Square circuit 6, 10, 11, 12, 13 ... Addition part 14 ... Switching means 15 ... Torque control unit 16 ... Determination means 1 ...

Claims (2)

In a chassis dynamometer that places a vehicle tire on a twin roller consisting of a road roller and a free roller, and uses a dynamometer as a power absorber to perform a vehicle test based on a time-vehicle speed pattern signal.
The vehicle tire radius is R, the road roller and free roller radii are r1 and r2, respectively, and the horizontal distance from the tire center point to the road roller center point and from the tire center point to the free roller center point is L1, respectively. When L2, the load setting traveling resistance F applied to the road roller is obtained by F = A + BV ² + (1 + dV / dt) × W cos θ ₁ + W cos θ ₂ when the vehicle is accelerated, and the vehicle is decelerated. A method for controlling a dynamometer, characterized by sometimes giving a value obtained by F = A + BV ² + W cos θ ₁ + (1 + dV / dt) × W cos θ ₂ .
Where A: rolling resistance of the vehicle, B: windage loss of the vehicle, V: detected vehicle speed, cos θ ₁ = (√ (R + r1) ² −L1 ² ) / (R + r1), cos θ ₂ =
(√ (R + r2) ² −L2 ² ) / (R + r2), W: vehicle mass, dV / dt: acceleration / deceleration. 2. The dynamometer control method according to claim 1, wherein the switching determination of the running resistance during acceleration and deceleration is performed with a waveform obtained by differentiating the detected vehicle speed signal.

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