JPS61204538A - Chassis dynamo for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To measure the power of a four-wheel drive vehicle almost in an actual run state by controlling rotational loads on dynamometers of front and rear wheels electrically on the basis of resistance loads allotted to the dynamometers of the front and rear wheels. CONSTITUTION:The run resistance loads Wa and electric inertial load Ya for the front wheels which are calculated in a simulation run by load arithmetic means 22 and 24 on the basis of a set ratio of driving force allotment are added together by an adder 62 for the front wheels and outputted as the allotted load Za of a dynamometer 12a for the front wheels. Thus, the rotational loads of dynamometers 12a and 12b are controlled electrically on the basis of allotted loads Za and Zb for the front and rear wheels to simulate a run of the four- wheel drive vehicle 100 on rollers 10a and 10b on the same condition with an actual run road.

Description

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

[Prior art] Chassis DAM is used to simulate and measure the power characteristics of a vehicle under running conditions. For example, when measuring the power characteristics of a four-wheel drive vehicle, it is necessary to measure the front and rear drive wheels of the four-wheel drive vehicle, respectively. The roller is brought into contact with the front wheel roller and the rear wheel roller, and a rotational load is applied to each roller according to the running condition of the vehicle.

In this way, the actual running of a four-wheel drive vehicle can be simulated on the chassis dynamometer, and the power of the four-wheel drive vehicle can be satisfactorily measured in a stopped state.

Conventionally, in such a chassis dynamometer, the rotational loads of the front wheel rollers and the rear wheel rollers are controlled by calculating the sum of the rotational loads of the front wheel rollers and the rear wheel rollers with the running load in the actual running state of the four-wheel drive vehicle. control to be equal,
Feedback control was also used to equalize the rotational speed of both rollers to prevent a speed difference between the front and rear wheels of a four-wheel drive vehicle.

[Problems to be Solved by the Invention] By the way, conventional chassis dynamometers that perform such differential speed O control reduce the speed to zero when a speed difference occurs between the front wheels and rear wheels of a four-wheel drive vehicle. Therefore, a force of (inertia of the roller) x (acceleration) acts from the front wheel roller or rear wheel roller toward the corresponding front wheel or rear wheel, and the differential speed is controlled to be zero.

However, the force applied to reduce the differential speed to 0 is
This force is different from the force applied to the front and rear wheels during actual driving of a four-wheel-drive vehicle. Therefore, conventional chassis dynamometers for four-wheel-drive vehicles measure the power of a four-wheel-drive vehicle by simulating actual driving and are not necessarily accurate. The problem was that it could not be done.

In particular, the front and rear wheels of today's four-wheel drive vehicles do not necessarily share the same amount of power, and depending on the performance and purpose of use of the vehicle, the amount of power shared between the front and rear wheels is different from the other. It is often set large.

When performing zero differential speed control on such a four-wheel drive vehicle as in the past, the load applied to the front and rear wheels of the vehicle when reducing the differential speed to zero is significantly different from that during actual driving, and the power measurement is difficult. cannot be carried out accurately, and effective countermeasures have been desired.

The present invention has been made in view of such conventional problems, and its purpose is to improve the actual driving condition by taking into account the driving force sharing ratio between the front wheels and rear wheels of a four-wheel drive vehicle. An object of the present invention is to provide a chassis dynamo for a four-wheel drive vehicle that can accurately reproduce power and perform good power measurements.

[Means for Solving the Problems] The chassis dynamo of the present invention includes a front wheel roller and a rear wheel roller on which the front and rear drive wheels of a four-wheel drive vehicle are placed in contact with each other, and the rotational load of each of these rollers is electrically controlled. A dynamometer for front wheels and a dynamometer for rear wheels are included, and the four-wheel drive vehicle is simulated running on the rollers and its dynamism is measured.

A characteristic feature of the present invention is that the four wheels simulate running on the rollers.
A driving state detecting means for detecting the speed and acceleration of the wheel drive vehicle, a sharing ratio setting means for inputting the driving force sharing ratio between the front and rear drive wheels of the four-wheel drive vehicle, and an inertia for inputting the reference inertial load of the four-wheel drive vehicle. a load setting means, a first load calculation means for calculating each running resistance load of the front wheels and rear wheels of the four-wheel drive vehicle based on the traveling speed and the driving force sharing ratio of the four-wheel drive vehicle, and the input reference inertial load. , a second load calculation means that calculates and outputs the electric inertia loads of the front wheels and the rear wheels corresponding to the detected acceleration based on the driving force sharing ratio and the preset fixed inertia loads of the front wheel rollers and the rear wheel rollers; a third load calculation means that adds the outputs of the first and second load calculation means and calculates a shared resistance load shared by the front wheel dynamometer and the rear wheel dynamometer;
The rotating load of each dynamometer for the front wheels and rear wheels is electrically controlled based on the shared resistance load outputted from the third load calculation means, and the rotation load of the dynamometer for the front wheels and rear wheels is electrically controlled, and the rotational load of the four-wheel drive vehicle is controlled in a state approximating actual driving. Its purpose is to measure power.

[Function] With the above configuration, when measuring the power of a four-wheel drive vehicle using the chassis dynamo of the present invention, the sharing ratio setting means can set the driving force sharing ratio between the front and rear drive wheels of the four-wheel drive vehicle. At the same time, the reference inertial load of the four-wheel drive vehicle is also set by the inertial load window installation means.

Here, the reference inertial load is given as the value of the vehicle weight itself.

In this way, when the driving force sharing ratio and the reference inertia load are set, the first load calculation means calculates each of the front wheels and rear wheels when the four-wheel drive vehicle is running at a constant speed based on the set driving force sharing ratio. Calculates and outputs running resistance load.

Further, the second load calculation means corresponds to the detected acceleration based on the thus set driving force sharing ratio, the reference inertial load, and the preset fixed inertial load of each roller for the front wheels and the rear wheels. Calculate the electrical inertia load on the front and rear wheels.

The running resistance loads and electrical inertia loads of the front wheels and rear wheels that have been tested in this way are added up by the third load calculation means, and the load is shared by the front wheel dynamometer and the rear wheel dynamometer. It is calculated and output as a resistance load, and load control of each dynamometer for the front wheels and rear wheels is performed based on the shared resistance load thus output.

By doing so, the chassis dynamometer of the present invention simply sets the driving force sharing ratio and reference inertia load for the front wheels and rear wheels of the four-wheel drive vehicle, and during actual driving, the chassis dynamometer of the four-wheel drive vehicle The driving load applied to the rear wheels is reproduced on the chassis dynamometer, making it possible to accurately measure the power of four-wheel drive vehicles.

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

FIG. 2 shows a preferred embodiment of the chassis dynamo for a four-wheel drive vehicle according to the present invention. Front wheel roller 1 on which the wheels 110 and 120 are placed in contact with each other
0a and rear wheel roller 10b, each of these rollers 1
The rotational shafts of dynamometers 12a and 12b are directly connected to 0a and 10b, and the rotational loads of rollers 10a and 10b are individually electrically controlled.

When measuring the power of a four-wheel drive vehicle, the front wheels 110 and rear wheels 120 of the four-wheel drive vehicle 100 are brought into contact with the corresponding front wheel rollers 10a and rear wheel rollers 10b, and the four-wheel drive vehicle 100 is The drive wheels 110 and 120 are fixed by a predetermined fixing means so as not to move due to rotation of the drive wheels 110 and 120, and simulated running is performed on the rollers 10a and 1Ob. At this time, the rotating rollers 10a and 10b function as an infinite flat road instead of the actual road surface, and the power measurement of the test four-wheel drive vehicle, that is, various dynamic driving performance tests, is performed on the same road as the actual road. Can be done under certain conditions.

A simulated driving state that approximates actual driving is created by applying a rotational load equal to the load applied to the front wheels 110 and rear wheels 120 of the four-wheel drive vehicle 100 during actual driving to the front wheel rollers 10a and the rear wheel rollers 10b. be done.

Here, when considering the running load applied to the front wheels 110 and rear wheels 120 of the four-wheel drive vehicle 100 during actual running, this running load includes a running resistance load and an inertial load.

The running resistance load is expressed as the sum of rolling resistance, windage, and slope resistance that occur when the vehicle is running at a predetermined speed, and the inertial load is the load that is applied when the vehicle is accelerated or decelerated. .

FIG. 1 shows the roller 10 using dynamometers 12a and 12b.
A control circuit that applies a rotational load similar to the actual running of the four-wheel drive vehicle 100 is shown at rollers 10a and 10b.
The running speed and acceleration of the four-wheel drive vehicle 100 running on the simulated road 10b are detected by the running state detection means 20, and the detected speed is detected by the first load calculation means 22 which calculates the running resistance load of the four-wheel drive vehicle 100. The detected acceleration is also supplied to a second load calculation means 24 that calculates the inertial load of the four-wheel drive vehicle 100.

In the embodiment, the running state detection means 20 includes a pair of pickups 26a and 26b that detect the rotational speed n a and ``nb of each roller ioa and iob, and a detected rotational speed n.
A pair of speed detectors 28a and 28b detect speeds v'a and vb of the front wheels 110 and rear wheels 120 of the four-wheel drive vehicle 100, respectively, based on the speeds a and nb.

It includes an average value calculator 30 that calculates the average value (2) of the detected speeds Va and vb, and an acceleration calculator 32 that calculates the average acceleration α of the four-wheel drive vehicle 100 based on the average speed V.

Then, the four-wheel drive vehicle 100 calculated by the average value calculation unit 30
The average velocity V' of the load calculation means 22 is supplied to the first load calculation means 22, and the average acceleration α calculated by the acceleration calculation unit 32 is supplied to the second load calculation means 24.

The characteristic feature of the present invention is that these first load calculation means 22
The running resistance load and inertia load of the front wheels and rear wheels calculated by the second load calculation means 24 are calculated by the four-wheel drive vehicle 10.
Calculated so that it is equal to the actual running state of roller 1.
The reason is that the rotational loads of 0a and 10b can be controlled.

Therefore, the device of the present invention includes a sharing ratio setting means for setting the driving force sharing ratio a:b of the front and rear drive wheels of the four-wheel drive vehicle, and in the embodiment, this sharing ratio setting means is It is formed using a front wheel sharing ratio setting device 34 that sets only the sharing ratio a of the front wheels 110. Then, the front wheel sharing ratio a set by the sharing ratio setting device 34 is outputted via the D/A converter 36, and this sharing ratio a is outputted to the inverter 4.
4 to (1-a) and output as the rear wheel driving force sharing ratio.

The first load calculating means 22 calculates the load on the four-wheel-drive vehicle 100 based on the traveling speed of the four-wheel-drive vehicle 100 and the set sharing ratio a:b.
The running resistance loads Wa and wb of the front wheels 110 and rear wheels 120 of 0 are calculated.

In the embodiment, the first load calculation means 30 inputs the average speed V output from the average value calculation unit 30 to the load setting device 38, and the four-wheel drive vehicle 100 inputs the average speed V outputted from the average value calculation unit 30.
Calculate the running resistance load W1 when the vehicle is running at a constant speed, that is, the sum W of the rolling resistance, windage loss, and gradient resistance of the vehicle when the vehicle is running at a constant speed V, and use the calculated value to calculate the running resistance load for the front wheels. 40 and rear wheel running resistance load calculator 42, respectively.

The load setting device 38 is well known to employ various methods such as a constant term setting method, a polygonal line approximation method, or a real value setting method, and in this embodiment, a device using a real value setting method is used. ing.

FIG. 3 shows the characteristic data of speed-running resistance load preset in the O-road setter 38 of the embodiment, and the running resistance load at each vehicle speed is sampled and set in advance. Values between samplings are approximated by a polygonal line by linear interpolation.

Based on the data shown in FIG. 3, the load setting device 38 calculates and outputs the torque corresponding to the detected speed as a running resistance load.

In addition, the setting device 34 outputs via the D/A converter 36.
The front wheel side driving force sharing ratio a is determined by one running resistance load calculator 4.
0, and is also input to the other running resistance load calculator 42, which converts it into the rear wheel drive force sharing ratio (1-a)-b via the inverter 44.

Then, the running resistance load calculator 40 calculates the running resistance load Wa −aW/(a+
b) is calculated and input to the third load calculation means 46.

Further, the rear wheel running resistance load calculator 42 calculates the rear wheel running resistance load Wb-bW/(a + 'b
) is calculated and input to the third load calculation means 46.

In this way, the first load calculating means 22 of the present embodiment calculates the respective running resistance loads Wa and w of the front wheels and rear wheels based on the front wheel 110 and rear wheel side driving force sharing ratios of the four-wheel drive vehicle 100.
b can be calculated.

As described above, in order to determine the running loads on the front wheels 110 and rear wheels 120 of the four-wheel drive vehicle 100, in addition to such running resistances WWa and wb, the inertial load during acceleration and deceleration of the vehicle must also be calculated. is the inevitable punishment.

By the way, in such a chassis dynamo, roller 10
a, 10b and a dynamometer 128.12b directly connected thereto.
Since there is a fixed mechanical inertia load, the front wheels 110 of the four-wheel drive vehicle 100 are
The inertial load applied to the rear wheel 120 is the sum of such fixed inertial load and the electrical inertial load applied via the dynamometers 12a and 12b.

This means that the pair of dynamometers 12a, 1
2b electrical inertia load is applied to the four-wheel drive vehicle 10 during actual driving.
This means that the control must be performed to a value obtained by subtracting each fixed inertia load on the front wheel low 510a side and the rear wheel low 510b side from the inertial load applied to the front wheels 110 and rear wheels 120 of zero.

Generally, the electric inertial load during acceleration/deceleration is obtained by subtracting a fixed inertial load from a reference inertial load representing the vehicle quantity itself, and multiplying this value by a control function that includes the acceleration of the vehicle.

For this reason, the device of the present invention uses the inertia load setting device 48 to set a value corresponding to the total weight of the four-wheel drive vehicle 100 as the reference inertia load, and then sets this value as the reference inertia load via the D/A converter 50. It is input to the load calculation means 24 of No. 2.

The second load calculation means 24 automatically calculates and outputs each electric inertia load of the front wheels 110 and the rear wheels 120 according to the detected acceleration based on the reference inertia load set in this way and the driving force sharing ratio. It is something to do.

In the embodiment, the second load calculation means 24' includes a pair of reference inertial load calculation units 52a, 52b and an adder 54a.
, 54b, fixed inertial load setters 56a, 56b, and electric inertial load calculators 58a, 58b.

The load calculation units 52a and 52b calculate a front wheel side standard inertia load and a rear wheel side standard inertia load based on the input standard inertial load and driving force sharing ratios a and b, and apply the calculation results to the corresponding adders. 54a.

54b.

Furthermore, each fixed inertia load of the front wheel roller 10a and the rear wheel roller 10b is set in advance in the fixed inertia load setters 56a and 56b, and these set values are applied to the corresponding subtractors 54a and 54b. Output.

The subtractors 54a and 54b calculate the front wheel roller 10a from the front wheel and rear wheel reference inertial loads input in this way.
and the fixed inertia load of the rear wheel roller 10b, and calculate and output each reference electric inertia load on the front wheel side and the rear wheel side.

And each electrical inertia load calculator 58 for front wheels and rear wheels.
a and 58b calculate the electric inertial loads Ya and Yb on the front wheel at the detected acceleration α based on the reference inertial loads and detected accelerations on the front and rear wheels input in this way, and calculate the third load. The direction is outputted to the calculation means 46.

This third load calculation means 46 adds the outputs of the first and second load calculation means 22.24 and calculates shared rotational loads Za and zb shared by the front wheel dynamometer 12a and the rear wheel dynamometer 12b. In the embodiment, the outputs of the computing units 40 and 58 are added to calculate the shared rotational load za for the front wheels.
, and a rear wheel adder 64 that adds the outputs of the calculators 42 and 60 to calculate and output the shared rotational load for the rear wheels.

Then, the respective shared rotational loads za and zb obtained in this way are applied to the front wheel roller 10a and the rear wheel roller 1, respectively.
0b to each load control circuit 70a and 70b.

These load control circuits 70a, 70b control the corresponding dynamometers 12a, 12b based on the input of the shared rotational loads za and zb, and provide rotational loads corresponding to the shared loads za and zb.

In order to perform such load control, the load control circuit 70 of the embodiment includes a load cell 72 that detects the rotational torque absorbed by the dynamometer 12, and a third The torque control circuit 7 includes a collation device 76 that collates the divided rotational load Z inputted from the load calculation means 46, and a torque control circuit 7 that collates the collated rotational load Z inputted from the load calculation means 46.
Thyristor unit 8 for controlling the current of the dynamometer 12 by 8
0 is controlled.

At this time, when the dynamometer 12 is controlled as a generator, the electric power generated there is fed back to the power source 82 side via the thyristor unit 80.

The chassis dynamo of the present invention has the above configuration, and its operation will be explained next.

First, when measuring the power of the test four-wheel drive vehicle 100,
The front wheels 110 and rear wheels 120 of the four-wheel drive vehicle 100 are placed in contact with the corresponding front wheel rollers 10a and rear wheel rollers 10b, respectively.

Then, the sharing ratio setting device 34 sets the sharing ratio a of the front wheels 110 of the four-wheel drive vehicle 100.

Here, the problem is what criteria should be used to set the driving force sharing ratio a:b. Conventionally, it was thought that such a driving force sharing ratio corresponded to the axle load sharing ratio between the front wheels and rear wheels of a four-wheel drive vehicle, but according to experiments, this driving force sharing ratio a:b corresponds to the front wheel and rear wheel axle load sharing ratio. It was found that this corresponds exactly to the drive power ratio of the center differential gear between the rear wheels.

Therefore, in the chassis dynamometer of this embodiment, the sharing ratio a of the front wheels 110 is set based on the driving force sharing ratio given by the center differential gear of the four-wheel drive vehicle.

At the same time, the inertial load setter 48 sets the vehicle ms of the four-wheel drive vehicle as the reference inertial load.

Then, the four-wheel drive vehicle 100 is driven by its drive wheels 110 and 12.
The vehicle body is fixed by a predetermined fixing means so that it will not move due to zero rotation, and simulated running is performed on the rollers 10a and 10b.

When the simulated running is started in this way, the first load calculating means 22 calculates the running resistance load W of the front wheels 110 and rear wheels 120 of the vehicle based on the set driving force sharing ratio a:b.
a and wb are determined, and the second load calculation means 24 similarly calculates the electrical inertia loads ya and Yb of the front wheels 110 and rear wheels 120 corresponding to the acceleration of the vehicle.

The running resistance load Wa and electrical inertia load Ya for the front wheels thus determined are added by the adder 62 for the front wheels and output as the shared load Za of the dynamometer 12a for the front wheels. Similarly, the calculated running resistance load wb and electric inertia load Yb for the rear wheels are added by the adder 64 for the rear wheels, and are calculated and output as the shared load zb of the dynamometer 12b for the rear wheels.

In the present invention, by electrically controlling the rotational loads of the front wheel dynamometer 12a and the rear wheel dynamometer 12b based on the shared loads Za and zb for the front wheels and the rear wheels output in this way. , the four-wheel drive vehicle 100 can be run in a simulated manner on the rollers 10a and 10b under the same conditions as the actual road.

In particular, according to the present invention, an optimal rotational load is applied to the rollers 10a and iob according to the driving force sharing ratio a:b of the four-wheel drive vehicle 100, and the differential speed between the two rotational speeds is controlled by O as in the conventional method. Therefore, it is possible to accurately reproduce the speed difference between the front wheels 110 and the rear wheels 120 that occurs when a four-wheel drive vehicle actually runs, and perform various power measurements with good accuracy.

In addition, in the chassis dynamometer of this embodiment, the setting device 3
4, so that only the front wheel side driving force sharing ratio a is set, and the rear wheel side driving force sharing ratio is automatically set based on the set value a, so that the driving force It becomes possible to easily and accurately set the sharing ratio a:b.

[Effects of the Invention] As explained above, according to the present invention, the driving force sharing ratio between the front and rear drive wheels of a four-wheel drive vehicle is set, and the front wheel roller and the rear wheel roller are controlled based on the set sharing ratio. Since the shared load can be controlled, it is possible to simulate driving a four-wheel drive vehicle on the front wheel rollers and rear wheel rollers under the same conditions as the actual driving conditions. It is also possible to faithfully reproduce the differential speed that occurs. As a result, according to the present invention, it is possible to accurately measure the power of various four-wheel drive vehicles in which the front wheels and the rear wheels have different driving force sharing ratios.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing a preferred embodiment of the chassis dynamo for four-wheel drive vehicles according to the present invention, FIG. 2 is an explanatory diagram of the external appearance of the chassis dynamo of the present invention, and FIG. It is a characteristic diagram of speed-running resistance load. 10a... Front wheel roller, 10b... Rear wheel roller, 12a... Front wheel dynamometer, 12b... Rear wheel dynamometer, 20... Running state detection means, 22... No. 1 load calculating means, 24... second load calculating means, 34... sharing ratio setting means, 46... third load calculating means, 48... inertial load setting means.

Claims (1)

[Claims] (1) Front wheel rollers and rear wheel rollers provided corresponding to the front and rear drive wheels of a four-wheel drive vehicle; a front wheel dynamometer and a rear wheel dynamometer connected to the rotating shafts of the respective rollers; A chassis dynamometer that measures the power of a four-wheel drive vehicle by electrically controlling the rotational load of each of the dynamometers, comprising: a running system that detects the speed and acceleration of the four-wheel drive vehicle that is running on the rollers in a simulated manner; a state detection means; a sharing ratio setting means for inputting a driving force sharing ratio between front and rear drive wheels of the four-wheel drive vehicle; an inertia load setting means for inputting a reference inertial load of the four-wheel drive vehicle; a first load calculation means that calculates running resistance loads on front wheels and rear wheels of a four-wheel drive vehicle based on speed and driving force sharing ratio; and input reference inertial load, driving force sharing ratio, and preset front wheels. a second load calculation means for calculating and outputting the electric inertia loads of the front wheels and the rear wheels corresponding to the detected acceleration based on the fixed inertia loads of the rollers for the front wheels and the rollers for the rear wheels; and the first and second load calculation means. a third load calculation means for adding the outputs and calculating a shared resistance load shared by the front wheel dynamometer and the rear wheel dynamometer, based on the shared resistance load output from the third load calculation means; A chassis dynamo for a four-wheel drive vehicle, which electrically controls the rotational load of each dynamometer for front wheels and rear wheels, and measures the power of the four-wheel drive vehicle in a state approximating actual driving.