JPS61120941A - Chassis dynamometer for four-wheel-driven vehicle - Google Patents

Abstract

PURPOSE:To enable a better running test, by making a four-wheel-driven vehicle run in simulation on a front wheel roller and a rear wheel roller on the conditions equal to those of actual running to duplicate the running accurately at a fixed speed and accelerated and decelerated speeds. CONSTITUTION:When a running performance test is performed for a sample four-wheel-driven vehicle, the front and rear wheels thereof are placed on a front wheel roller 10a and the rear wheel roller 10b respectively, the body thereof is fixed by a specified fixing means and then, an simulated running is started. In this process, the total running resistance load L0 is computed as applied on the front and rear wheels of the four-wheel-driven vehicle in the actual running identical to the simulated running by means of a load comput ing circuit 16 while the load share ratio of a:b of the front and rear wheels is outputted with a share ratio setting circuit 24 corresponding to the accelera tion alpha of the vehicle. Based on the total running resistance load L0 and the load share ratio a:b thus outputted, the share resistance loads LA and LB of the front wheel roller 10a and the rear wheel roller 10b are computed and given the front wheel roller 10a and the rear wheel roller 10b with DC generators 12a and 12b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a chassis dynamometer for a vehicle, particularly a chassis dynamometer for a four-wheel drive vehicle.

[Prior Art] Chassis dynamometers that perform various driving performance tests on automobiles, such as pattern driving tests such as 10-mode tests, have been well known. Various tests are conducted on the test vehicle under conditions similar to actual driving, with the drive wheels of the test vehicle in contact with rollers whose load characteristics are arbitrarily controlled.

In the running performance test of a four-wheel drive vehicle using such a chassis dynamometer, the drive wheels of the four-wheel drive vehicle, that is, the front wheels and rear wheels, are brought into contact with the front wheel roller and the rear wheel roller, respectively. This is done by applying a load to each roller depending on the running condition of the vehicle.

By the way, in such a four-wheel drive vehicle, the load sharing ratio between the front wheels and the rear wheels is different. Therefore, in a chassis dynamometer for such a four-wheel drive vehicle, the front wheel load sharing ratio is different depending on the load sharing ratio between the front and rear wheels. It is necessary to control the load characteristics of the rollers and rear rollers.

For this reason, conventional four-wheel drive chassis dynamometers
Sharing ratio control is performed in which the load sharing ratio of the front wheel rollers and the rear wheel rollers is always controlled in accordance with the constant speed running state of the vehicle.

[Problems to be solved by the invention] 1. However, a chassis dynamometer for a four-wheel drive vehicle using such sharing ratio control cannot be used when the four-wheel drive vehicle is running at a constant speed. Although it is possible to faithfully reproduce the actual driving conditions and obtain good test results, it is not possible to faithfully reproduce the actual driving conditions of the vehicle if the vehicle is being accelerated or decelerated at a predetermined acceleration. The drawback was that accurate test results could not be obtained.

In other words, the load sharing ratio between the front wheels and rear wheels of a four-wheel drive vehicle is
The load is always constant when driving at a constant speed, but when the vehicle accelerates, the rear of the vehicle sinks and the load sharing ratio of the rear wheels increases, and when the vehicle decelerates, the front of the vehicle sinks and the load sharing ratio of the front wheels increases.

However, conventional chassis dynamometers for four-wheel drive vehicles cannot reproduce such fluctuations in the load sharing ratio of the front and rear wheels during acceleration and deceleration of the vehicle, and as a result, the positive FK1 during acceleration and deceleration cannot be reproduced. The drawback was that it was not possible to conduct thorough driving performance tests.

Another possibility is to use an arm or the like to forcibly control the front or rear of the vehicle body to sink in order to simulate the actual driving conditions during acceleration and deceleration, but it is difficult to create a chassis that uses such a method. In a dynamometer, the sink depth of the car body is uniformly fixed by the arm, making it impossible to simulate the vertical direction of the car body that occurs during acceleration or deceleration. The drawback was that accurate driving performance tests could not be conducted.

Purpose of the Invention The present invention was made in view of such conventional problems, and its purpose is to accurately reproduce the constant speed driving and acceleration/deceleration driving of a four-wheel drive vehicle, and to conduct a good driving performance test. An object of the present invention is to provide a chassis dynamometer for four-wheel drive vehicles that can perform the following functions.

[Means for Solving the Problems] The chassis dynamometer for a four-wheel drive vehicle of the present invention has a front wheel roller and a rear wheel roller in contact with the front and rear drive wheels of a test four-wheel drive vehicle. This allows a four-wheel drive vehicle to simulate driving while applying a predetermined load.

Here, the total running resistance load of the four-wheel drive vehicle that simulates running on the rollers is calculated by a load calculation circuit based on the running speed of the four-wheel drive vehicle.

Furthermore, the acceleration of the four-wheel drive vehicle running on the rollers is detected by an acceleration detector, and the load sharing ratio between the front wheels and the front wheels of the four-wheel drive vehicle, that is, the load sharing ratio between the front wheel roller and the rear wheel roller. is calculated by the sharing ratio setting circuit based on the detected acceleration.

The characteristic feature of the present invention is to accurately calculate the load sharing ratio of the front wheels and rear wheels when a four-wheel drive vehicle is running at a constant speed and during acceleration/deceleration, and to control the load characteristics of the front wheel rollers and the rear wheel rollers. It's about doing.

For this reason, the sharing ratio setting circuit of the present invention comprises: a standard load sharing ratio setting device in which standard load sharing ratios are set for each running state during acceleration running, constant speed running, and deceleration running; and the standard load sharing ratio setting device based on the detected acceleration. A sharing ratio selector that selects and outputs a standard load sharing ratio according to the driving condition from the sharing ratio setting device, and a parameter gain used for correcting the standard load sharing ratio during acceleration and deceleration driving are set. a parameter setter; a parameter selector that selects and outputs a parameter gain from the parameter setter based on detected acceleration; and a parameter selector that selects and outputs a parameter gain from the parameter setter based on detected acceleration; a correction value calculator that calculates a correction value for the load sharing ratio according to the actual driving condition of the four-wheel drive vehicle by adding and subtracting the selection output of the sharing ratio selector and the calculation output of the correction value calculator; The present invention is characterized by comprising: a computing unit for outputting a sharing ratio;

Then, based on the total running resistance load calculated by the load calculation circuit and the load sharing ratio calculated by the sharing ratio setting circuit, the shared resistance load to be shared by the front wheel zero roller and the rear wheel roller is calculated, and the front wheel The load characteristics of the rear wheel rollers and rear wheel rollers are controlled to test four-wheel drive vehicles under conditions that approximate actual driving.

[Function] Therefore, according to the chassis dynamometer for a four-wheel drive vehicle of the present invention, during constant speed driving, the standard load sharing ratio setting device selects and outputs the standard load sharing ratio during constant speed driving. The load characteristics of the front wheel roller and the rear wheel roller are controlled using the selected standard load sharing ratio.

In addition, when the vehicle is accelerating or decelerating, the standard load sharing ratio during acceleration or deceleration is selectively output from the standard load sharing ratio setting device, and the standard load sharing ratio selected and output in this way is A correction value for correcting the deviation from the actual sharing ratio is calculated and output from the correction value calculator. Then, add or subtract the standard load sharing ratio and the correction value to create four-wheel drive! The load sharing ratio during actual acceleration/deceleration of the ILJ vehicle is calculated. Then, based on the load sharing ratio determined in this way, the load characteristics of the front wheel roller and the contact wheel roller are controlled.

In this way, the four-wheel drive one-ton chassis dynamometer of the present invention accurately reproduces constant speed running and acceleration/deceleration running of a four-wheel drive vehicle on the front wheel rollers and rear wheel rollers. This makes it possible to perform various driving performance tests.

[Example] Next, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a preferred embodiment of the chassis dynamometer for a four-wheel drive vehicle according to the present invention. A front wheel roller 10a and a rear wheel roller 10b on which the driving wheels, that is, the front wheel and the rear wheel are placed in contact with each other, and each roller 10a directly connected to each of these rollers 10a and 10b.

DC power generator 12a, 1 that controls the rotational resistance load of 10b
2b and wo include.

Then, a front wheel roller 10a and a rear width roller 1 corresponding to the front wheels and rear wheels of the test four-wheel drive vehicle to be tested for driving performance are provided.
0b, and fix the four-wheel drive vehicle by a predetermined fixing means so that it does not move due to rotation of the drive wheels,
A simulated run is made on the rollers 10a and 10b. As a result, each of the rotating rollers lQa and 10tl is transformed into an actual road surface, functioning as an infinite flat ring road, and a dynamic driving performance test of a four-wheel drive vehicle is conducted under the same conditions as the actual road. It is something.

Here, in a pseudo driving state that approximates actual driving, a resistance load equal to the resistance load applied to the front wheels and rear wheels during actual driving of a four-wheel drive vehicle is applied to the front wheel roller 10a and the rear wheels using DC generators 12a and 12b. It is formed by applying a voltage to the roller 10b.

In order to perform such resistance load control, in the apparatus of the embodiment, the rotation speed of the DC motor 12a is detected by the rotation speed detector 13, and the speed on the rollers 1Qa, 10b is controlled by the speed detector 14 based on the detected rotation speed. The vehicle's traveling speed is detected.

And the traveling speed detected in this way is.

The total running resistance load is supplied to the load calculation circuit 16 and is applied by the load calculation circuit 16 to the front wheels and rear wheels of the vehicle at the relevant running speed. Calculate.

In the embodiment, this load calculating circuit 16 includes a load setting device 18 and an electric flywheel 20. Then, the load setting device 18 determines the resistance load when the vehicle is traveling at a constant speed at the detected speed based on the traveling speed of the vehicle. Further, the electric flywheel 20 calculates the acceleration of the vehicle by differentiating the detected speed,
Find the inertial resistance load at the time of the acceleration. Then, the constant speed running resistance load and the inertial resistance load obtained in this manner are added by an adder 22 and outputted as the total running resistance load Lo. It is output like this. represents the total running resistance load on each drive wheel, front and rear wheels, under the current speed and acceleration of the four-wheel drive vehicle.

Incidentally, the proportion of the total running resistance load shared by the front wheels and rear wheels of a four-wheel drive vehicle changes from time to time based on the running conditions, particularly changes in acceleration.

A characteristic feature of the present invention is that it accurately reproduces changes in the load sharing ratio between the front wheels and rear wheels of a four-wheel drive vehicle due to changes in acceleration, and allows the front wheel roller 10a and the rear wheel roller 10b to By applying the same shared resistance load as when driving, it is possible to perform various dynamic driving performance tests of four-wheel drive vehicles under conditions similar to actual driving.

Therefore, the device of the present invention includes an acceleration detector 24 that differentiates the detection output of the speed detector 14 and detects the acceleration α of the four-wheel drive vehicle, and a front wheel roller 10a and a rear wheel roller 10a based on the detected acceleration α. A sharing ratio setting circuit 26 for calculating the load sharing ratio a:b of the rollers 10b is provided.

Fig. 2 shows the correlation between the acceleration α obtained during actual driving on an actual road in four-wheel drive in this example and the load sharing ratio of the front wheels and rear wheels at that time. .

In addition, in the same figure, the load sharing ratio of the rear wheels is shown in parentheses as a percentage.
Displayed.

As is clear from such load sharing ratio data, the load sharing ratio of the front wheels and rear wheels of a four-wheel drive vehicle changes almost linearly with changes in acceleration α, and also changes during acceleration and deceleration. The slopes of straight lines often differ.

Taking these points into consideration, the load sharing ratio setting circuit 26 of the present invention sets the standard load sharing ratio A:B in each driving state of the four-wheel drive vehicle during acceleration, constant speed, and deceleration. It includes a standard sharing ratio setter 28.

In the embodiment, this sharing ratio setting device 28 sets α=o as the standard load sharing ratio during acceleration driving, and the load sharing ratio when ig is A: B = 42.5 (X): 57.5 (
%) is set, and the standard load sharing ratio in a constant speed running state is set to - sharing ratio A:B = 50(%):50(X) when α-0. The load sharing ratio setting device 28b during constant speed running and the load sharing ratio when α=-0, 1 fJ as the standard load sharing ratio during deceleration running A: B = 60 (%): 40 (X)
is composed of a setting sales ratio setting device 28c during deceleration traveling.

Based on the detection output α of the acceleration detector 24, the sharing ratio setting circuit 26 of the embodiment determines whether the vehicle is running at an accelerated speed, running at a constant speed, or
It has a running state discriminator 32 that determines whether the running state is deceleration running, and the sharing ratio selector 30 selects each setting device 28 based on the running state detected by the running state discriminator 32.
a, 28 b, 28 c.

A standard load sharing ratio A:B corresponding to the running condition is selected from the standard load sharing ratio A:B and the ratio is supplied to the sharing ratio calculator 34.

By the way, when the vehicle accelerates or decelerates, the load sharing ratio between the front wheels and the rear wheels is a:b depending on the acceleration α.
changes. Therefore, when the vehicle is accelerating or decelerating, it is possible to correct the standard load sharing ratio A:B to match the actual load sharing ratio a:b according to the magnitude of the detected acceleration α. It becomes necessary.

Here, focusing on the load sharing ratio a of the front wheels of the vehicle, as is clear from the data shown in FIG. is tanθ1-61 with respect to acceleration α, and when the vehicle is decelerating, the slope of the characteristic curve is tanθ2=02.

Therefore, for example, if we focus on the load sharing ratio when the vehicle is decelerating at α=-0,2(l),
The sharing ratio is a:b=70(%):3Q(%), and the sharing ratio setter 28C1 during deceleration running: set standard load lfl ratio (7)A:B=60(%):4
Compared to 0 (%), +10 (%) for the front wheels and -10 (%) for the rear wheels.
) It is understood that there is an error.

Therefore, if the correction value of the load sharing ratio of the front wheels when the vehicle is accelerating or decelerating is K (%), then this correction value K is determined as follows. In other words, the correction value when the vehicle is accelerating is K=G+(α-0,1) (1), and the correction value when the vehicle is decelerating. The value is = G2 (α + 0.1) ・・・・・・(2
).

In order to perform such calculations, the sharing ratio setting circuit 2 of the present invention
6 is a parameter gain G used for correcting the standard load sharing ratio when the vehicle is accelerating and decelerating.
2, and a parameter selector 38 that selects and outputs the parameter gain G from the parameter setter 26 based on the detected acceleration.

In the embodiment, the parameter setting device 36 includes an acceleration gain setting device 36a in which a parameter gain G1 during acceleration is set, and a deceleration gain setting device 36C in which a parameter gain G2 during deceleration is set.

Based on the detection output of the driving state discriminator 32, the parameter selector 38 selects a parameter gain of 01 from the setter 36a when the vehicle is accelerating, and selects a parameter gain of 01 from the setter 36a when the vehicle is decelerating. If there is, setter 36c
The parameter gains of G2 are selected from , and these selected gains are output to the correction value calculator 40 .

The correction value calculator 40 uses the parameter gain G thus output and the detected acceleration α output from the acceleration detector 24 to calculate the correction value K using the equation (1) or (2). The calculated value is output to the sharing ratio calculator 34. Note that this correction value calculator 40 outputs =O when α=0.

The sharing ratio calculator 34 adds and subtracts the standard load 7 sharing ratio A:B supplied from the sharing ratio selector 30 and the correction value output from the correction value calculator 40, and calculates the actual value of the four-wheel drive vehicle. A load sharing ratio a:b corresponding to the running condition is calculated and output to the setting circuit 42.

In the embodiment, the calculation for determining a:b is performed based on the following equation.

a=A + K (3) b=B −K
(4) In this way, according to the present invention, the standard load sharing ratio A:B, which is set in advance according to acceleration driving, constant speed driving, and deceleration driving, is adjusted based on the detected acceleration α. The load sharing ratio a:b is corrected to match the load sharing ratio a:b according to the actual driving condition, and the ratio a:bh<setting circuit 42 is supplied with the load sharing ratio a:bh.

In the above embodiment, as shown in FIG. 2, the slope of the sharing ratio characteristic curve is different when the vehicle accelerates and when the vehicle decelerates. However, the present invention is not limited to this. Needless to say, it can be used even when the sharing ratio characteristic curves during deceleration have the same slope.

In this way, when the load sharing ratio a:b between the front wheels and the rear wheels is output, the sharing resistance setting circuit 42 sets the sharing resistance load L of the front wheel roller 0a and the rear wheel roller 0 based on the following equation.
b's shared resistance load.

is calculated based on the following formula, LB=-L.

a+b The shared resistance load LA obtained in this way.

are the front wheel roller 0a and the rear wheel roller 0b, respectively.
is supplied to each load control circuit 44a, 44b.

Then, each load control circuit 44a, 44b controls the corresponding DC generator 12a, 12b based on the input from such shared resistance setting circuit 42, and controls the front wheel roller 0a and the rear wheel roller 0b. Shared resistance load,
Apply a rotational resistance load corresponding to .

In order to perform such load control, the load control circuit 44 of the embodiment includes a load cell 46 that detects the rotational torque absorbed by the DC generator 12, and a detection torque of the load cell 46 that is input via an amplifier 48 and a setting circuit. 42, and a torque control circuit 52 controls the current control thyristor unit 54 of the DC generator 12 so that both matching data match.

The chassis dynamometer of the present invention has the above configuration,
Next, its effect will be explained.

First, when performing a running performance test on a test four-wheel drive vehicle, the front wheels and rear wheels of the four-wheel drive vehicle are placed in contact with the front wheel roller Oa and the rear wheel roller Ob, respectively. and,
The vehicle body is fixed by a predetermined fixing means so that the vehicle does not actually move due to the rotation of the drive wheels of the four-wheel drive vehicle, and the roller 0a.

On 10b, pseudo-driving of the four-wheel drive vehicle is started.

In this manner, when the simulated running is started, the load calculation circuit 16 calculates the total running resistance load that is applied to the front wheels and rear wheels of the four-wheel drive vehicle during actual running similar to the simulated running. is calculated, and at the same time, the load sharing ratio a:b of the front wheels and rear wheels corresponding to the acceleration α of the vehicle is outputted by the sharing ratio setting circuit 24.

Then, the total running resistance load output in this way.

and load sharing ratio a:b1. :Based on front wheel roller 0
a, shared resistance load L, L of rear wheel roller 0b
is calculated, and the DC generator 12a.

8B 12b for front wheel roller 0a and rear wheel a-ra 1
A shared resistance load, L8, is applied to 0b.

^ Therefore, in the present invention, for example, when the acceleration α=O, as is clear from FIG.
The load sharing ratio of a and rear wheel roller 0b is 50 (X)
: Set to 50 (%), and for example, if the acceleration α is α−
In the case of 0.20, the load sharing ratio of the front wheel roller 0a and the rear wheel roller 0b is 35 (X): 75 (%
) is set.

Thus, according to the device of the present invention, each roller 0a,
When a four-wheel drive vehicle is pseudo-traveling on roller 10b, each roller 0a, 10b is rotated with a shared resistance load L8 corresponding to the acceleration α.

As a result, with the chassis dynamometer of the present invention, it becomes possible to accurately conduct various dynamic running performance tests of a four-wheel drive vehicle, such as O-400 m+ acceleration characteristic tests, on the rollers 0a and 10b.

[Effects of the Invention] As explained above, according to the present invention, it is possible to make a four-wheel drive vehicle run in a simulated manner on the front wheel rollers and the rear wheel rollers under the same conditions as the actual driving conditions, and the four-wheel drive vehicle It becomes possible to accurately perform various dynamic driving performance tests on vehicles.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing a preferred embodiment of a chassis dynamometer for a four-wheel drive vehicle according to the present invention, and FIG. 2 is a characteristic diagram of the load sharing ratio between the front wheels and rear wheels of the vehicle. 10a... Front wheel roller 12b... Contact wheel roller 16... Load calculation circuit 24... Sharing ratio setting circuit 26... Limit circuit 28... Sharing ratio resistance setting circuit 30... Sharing Ratio setter 34... Sharing ratio calculator 36... Parameter setter 38... Parameter selection humidity 40... Correction value calculator 42... Setting circuit.

Claims (1)

[Claims] (1) A front wheel roller and a rear wheel roller that come into contact with the front and rear drive wheels of a test four-wheel drive vehicle and cause the four-wheel drive vehicle to simulate running while applying a predetermined load to the drive wheels, and simulated running on the rollers. a load calculation circuit that calculates the total running resistance load during actual driving of the four-wheel drive vehicle based on the traveling speed of the four-wheel drive vehicle; an acceleration detector that detects the acceleration of the four-wheel drive vehicle; a sharing ratio setting circuit that calculates a load sharing ratio between a front wheel roller and a rear wheel roller, and the sharing ratio setting circuit is configured to calculate a standard load in each driving state during acceleration driving, constant speed driving, and deceleration driving. a standard load sharing ratio setter in which a sharing ratio is set; a sharing ratio selector that selects and outputs a standard load sharing ratio according to the driving condition from the standard load sharing ratio setter based on detected acceleration; a parameter setter in which a parameter gain is set for use in correcting the standard load sharing ratio; a parameter selector that selects and outputs a parameter gain from the parameter setter based on detected acceleration; a correction value calculator that calculates a correction value between the standard load sharing ratio and the actual load sharing ratio based on the output and the detected acceleration; and a selection output of the sharing ratio selector and a calculation output of the correction value calculator. a sharing ratio calculator that adds and subtracts and calculates and outputs a load sharing ratio according to the actual running condition of the four-wheel drive vehicle; A chassis for a four-wheel drive vehicle characterized by calculating the shared resistance load to be shared, controlling the load characteristics of front wheel rollers and rear wheel rollers, and testing the four-wheel drive vehicle under conditions approximating actual driving. Dynamometer.