JP2805926B2 - Chassis dynamometer control system for four-wheel drive vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chassis dynamometer control system for a four-wheel drive vehicle, and more particularly, to a driving resistance control method used for an exhaust gas and fuel efficiency test for certification of a new type vehicle. .

B. Summary of the Invention The present invention relates to a chassis dynamometer control system for a four-wheel drive vehicle used for an exhaust gas and fuel economy test for certification of a new type of vehicle, comprising two input shafts of a constant velocity machine and a chassis dynamometer of a front wheel or a rear wheel. A shaft torque meter disposed one by one with the shaft end of the meter, a shaft torque meter output converter that matches the output of the shaft torque meter with a predetermined electric output, and a total of the outputs of the two converters An expensive adder that subtracts the output of the adder from the load command signal, thereby eliminating the need for an expensive and large-space constant-velocity machine, even when the front-wheel drive force is larger than the rear-wheel drive force. It is an object of the present invention to provide a technique capable of performing high-precision running resistance control by negating a loss of a speed unit, and independently measuring driving forces generated by front and rear wheels.

C. Conventional technology Chassis dynamometer is a device that performs a running test by placing a car on a belt-like or roller-like movable road surface, and is very important for understanding the function and performance of the whole car. Yes, in general, the main purpose is to replace testing on the test course with laboratory testing. Some tests can be performed only on a chassis dynamometer, such as an exhaust gas test, and others cannot achieve stable test conditions on a test course, such as a noise test and a high / low temperature test. Recently, demands for diversification, stability and environmental friendliness of vehicles such as front-wheel drive vehicles and four-wheel drive vehicles (4WD vehicles) have increased, and specification requirements for test automation and labor saving have also become sophisticated and complex.

Four-wheel drive vehicles are increasingly being used in passenger cars, wagon vehicles, commercial vehicles, and the like, but the systems are extremely diverse, and there is a good possibility that new systems will appear in the future. The current classifications are as follows.

(1) Part-time (switchable type) This method has been used for jeep and land cruiser, etc. Conventionally, good roads are driven by two wheels, and rough roads (rough terrain, steep slopes,
On a slippery runway, etc., front and rear are connected by a clutch and four-wheel drive is performed.

(2) Full time (constant type) With center differential; Basically, the front and rear driving force sharing ratio is 50:50.

With a slip element; the front and rear shafts are connected by a viscous joint or the like. On a good road, the main drive wheels share most of the driving force, and on a slippery road, the force transmitted to the driven side automatically increases.

Traction control (TRC): Automatically changes the driving force distribution between the front and rear wheels by detecting acceleration during acceleration and tire slip to maximize the driving force of the car.

A case where a chassis dynamometer is applied to a vehicle of each of the above types will be discussed.

For a part-time vehicle, a front and rear dynamometer with a 50:50 braking force is sufficient even with a chassis dynamometer with separate front and rear axes. The same applies to vehicles with a center differential. On the other hand, for a four-wheel drive vehicle with a slip element or traction control, a method of calculating a slip ratio based on load simulation or a method of variable load sharing control is used, and the difference between rotating bodies described in Japanese Utility Model Laid-Open No. 63-53108 is used. They also use a rotation control method.

In the diversification of four-wheel drive vehicles, when the above-mentioned test of a vehicle with a slip element or a traction control type is operated on a chassis dynamometer of a front-rear axis separation type, the conventional control has a large difference between the front and rear wheels when the driving state changes. A speed difference occurs. As a countermeasure for this, it is conceivable to change the differential speed detection of the digital synchronous control device from a sampling method for every fixed period to a continuous comparison method, and a good result is obtained.

However, in spite of these contrivances, in the above-mentioned conventional apparatus, a slight difference in speed between front and rear occurs. In particular, at the time of starting, a considerably large front-rear speed difference is generated due to the provision of a circuit for automatically shutting off the dynamometer braking in a very low speed region where the reverse rotation of the roller must be absolutely prevented. In addition, the setting of the front and rear braking force sharing circuits becomes somewhat complicated, so that maintaining the accuracy of the control circuit becomes troublesome. In such a case, the sixth
Front and rear separation type with constant velocity machine as shown in FIG.
It is necessary to provide a front and rear and left and right separated type chassis dynamometer with a constant speed machine as shown in FIG. (B). When testing a four-wheel drive vehicle with such a type of chassis dynamometer, FIG. It is common to apply a running resistance load and an electric inertia load equally to two dynamometers as shown in FIG.
Although not shown, the speed of each dynamometer is individually controlled, and the speed can be controlled in conjunction with two dynamometers, or the running resistance control or the electric inertia control can be performed on the front wheel or the rear wheel alone. It is also possible to attach a detachable flywheel symmetrically or asymmetrically to each of the front and rear shafts.

In FIG. 7, reference numeral 70 denotes load command signal generating means, which differentiates the detection value from the DC dynamometer for the front wheel roller with differentiating means 71,
Mechanical loss setting means (ML) 72 and running resistance setting means (RL)
Entered in 73. The output of the differentiating means 71 is
After being multiplied by the outputs of the calculating means 74 and the inertia setting means 75 and the multipliers 76 and 77, the output of the mechanical loss setting means 72 and the output of the running resistance setting means 73 are added and subtracted by the adding means 78.

In the above device, the mechanical loss of the dynamometer is measured in advance and the mechanical loss is set in the mechanical loss setting means 72 in a no-load state, and the traveling resistance is measured in advance while the vehicle speed is traveling at a constant speed on a flat road. This is set in the resistance setting means 73, and the difference between the outputs is given to the dynamometer as a braking force command. In addition, the differentiating means 71 obtains an inertia resistance component that cannot be simulated due to mechanical inertia by differentiating a vehicle speed signal detected from the rollers via a vehicle speed detecting means (F / V). Is multiplied by the difference between the mechanical inertia amount and the set inertia amount to perform electric inertia control. This electric inertia resistance component is also equally distributed to the front and rear dynamometers A and B similarly to the running resistance component. Note that the addition of the front and rear wheel speeds is not necessarily required, and either one of the front and rear wheels may be used alone, but the addition improves the stability. Dynamometer control units 79a and 79b
May be torque control instead of current control, but current control is a simpler circuit. As a torque detection circuit, use of a torque response improvement circuit and the like described in Japanese Patent Publication No. 62-42478 has been considered.

In this figure, instead of sending the output of a mechanical loss setting means (ML) 72 to an adding means 78 and subtracting it from a braking force command, a braking force detecting means connected to a flywheel (FW) as a power absorbing device is used. That is, through a DC dynamometer (DCDY),
There is also a method of adding the ML output to the total value of the braking forces of the front and rear dynamometers obtained from the load cell (LC), and the same effect can be obtained in terms of control.

The circuit around the dynamometer will be described. The roller rotation signal detected by the pulse pickup (PG) is converted into a voltage by a frequency converter (F / V), and the vehicle speed of the front wheel and the rear wheel is processed by required coefficient processing. After obtaining (roller peripheral speed), these are added to obtain an average vehicle speed, and an average acceleration signal is obtained by differentiating this signal. However, the front wheel speed and the rear wheel speed are independently differentiated, After obtaining the front wheel acceleration and the rear wheel acceleration, respectively, these may be added and subjected to coefficient processing to obtain an average acceleration signal.

D. Problems to be Solved by the Invention However, in the device as described above, a load transmission loss caused by a constant speed machine during operation becomes a problem. In other words, when testing a vehicle having characteristics improved by the new synchronous control as described above, the front wheel driving force is larger than the rear wheel driving force, but an equal braking force is applied when measuring the power. As a result, the surplus portion of the vehicle driving force transmitted to the front wheel rollers is transmitted to the rear wheel rollers via the constant velocity machine, where it is absorbed or balanced by the action-reaction law. . At this time, the loss that occurs in the constant velocity machine is
Naturally, it is larger than the loss that occurs during no-load operation. For example, if a bevel gear is used in a constant velocity machine, the loss of the transmission torque proportional to the bevel gear is normally 3 to 5% of the transmission torque, and the loss generated in the two bevel gears reaches 6 to 10%. When the loss occurs, the control accuracy of the running resistance control is significantly reduced.

Another problem is that, in the above-described conventional configuration, since the front and rear wheels are connected by a constant velocity machine, the driving force generated by the vehicle cannot be separated back and forth. Therefore, in order to separate the front and rear driving force, a so-called wheel torque meter must be mounted on all the driving wheels of the test vehicle.

The present invention has been made in view of such a problem, and does not require an expensive and large-sized constant velocity machine. Even when the front wheel driving force is larger than the rear wheel driving force, the loss of the constant velocity machine is reduced. On the contrary, it is an object of the present invention to provide a chassis dynamometer control system for a four-wheel drive vehicle capable of performing high-accuracy running resistance control and independently measuring driving forces generated by front and rear wheels.

E. Means for Solving the Problems Means for solving the above problems in the present invention are a constant velocity machine connecting both shaft ends variably with an axial center distance, rollers for front wheels and rear wheels, and a rotational speed of the rollers. Or a vehicle speed detecting means for detecting a peripheral speed, a power absorbing device coupled to each roller, a braking force detecting means for detecting a torque of the power absorbing device, a dynamometer control device for independently controlling the power absorbing device, A traveling resistance setting means for setting a steady traveling resistance of the test vehicle as a vehicle speed function, and an inertia setting means for a fixed mechanical mechanism are provided. In the chassis dynamometer control system for a four-wheel drive vehicle instructing the dynamometer control device of the above, one is disposed between each of the two input shafts of the constant velocity machine and the shaft end of the front or rear chassis dynamometer. Established A torque meter, a shaft torque meter output converter that matches their outputs to a predetermined electrical output, and an adder that sums the outputs of the two converters, and subtracts the output of the adder from the load command signal. And a product of the average acceleration signal detected from the roller side of the chassis dynamometer and the output of the inertia setting means, and the average acceleration signal and the output of the mechanical inertia detection calculation means. It is also possible to subtract a difference value from the multiplied value of the load command signal from the load command signal, and connect a dynamometer control device for performing torque control by branching / inputting a signal output from the control force detecting means to the distributor, and It is also possible to directly input a load command signal to the container.

F. Operation The chassis dynamometer of the present invention includes front and rear wheel rollers, a power absorbing device coupled to each roller, and, if necessary, a variable inertia type coaxially coupled to the power absorbing device. It consists of a flywheel, a moving device that moves these units to minimize the eccentricity of the shaft, a constant-speed machine that connects both shaft ends with a variable shaft center distance via a clutch, and the rotational speed of each roller Or, a vehicle speed detecting means for detecting a peripheral speed, a detecting means for detecting an absorbing braking force (torque) of a power absorbing device, a dynamometer control device for independently controlling the power absorbing device, and a steady running resistance of the test vehicle. A running resistance setting means for setting and outputting a desired vehicle speed function and an inertia setting means for a fixed mechanical mechanism including the variable flywheel are provided.

The amount of electric inertia is calculated from the difference between the sum of inertia of the two front and rear chassis dynamometers and the constant inertia and the set amount of inertia, and the amount of electric inertia is set manually or automatically. Further, the machine loss setting means sets the loss of all the machines as a vehicle speed function, and outputs a machine loss signal according to the vehicle speed input. The two front and rear vehicle speed signals are averaged, and an average acceleration signal is obtained by differentiating the average vehicle speed signal. When the average acceleration signal is multiplied by the set amount of the electric inertia, an electric inertia braking force command signal is output. The output is added to the output from the running resistance setting means, and the mechanical loss signal is subtracted therefrom. A command signal is output. On the other hand, the absorption braking force of the two dynamometers is added, and the output is subtracted from the load command signal to obtain a braking force deviation signal. This is performed by the control servo amplifier, and the result is distributed to the front and rear dynamometer control units by the distributor.

In such a chassis dynamometer, in the present invention, one shaft torque meter is disposed between each of two input shafts of the constant velocity machine and the shaft ends of the front and rear chassis dynamometers. Their outputs are matched to a predetermined electrical output by a shaft torque meter output converter. The outputs of the two converters are added together and then subtracted from the load command signal.

In the present invention, instead of the running resistance setting means in the above device, the average acceleration signal is multiplied by the output of the inertia setting means, while the average acceleration signal is multiplied by the output of the mechanical inertia detection calculating means, and The electric inertia braking force command signal may be obtained by subtracting the latter multiplication result from the multiplication result.

Further, in the present invention, the dynamometer control device in the above device performs the torque control by branching and inputting the signal of the braking force detecting means, and directly inputs the load command signal to the distributor. Is also good.

G. Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram of one embodiment of the present invention. In the figure,
1 is a constant velocity machine, 2 is rollers for front and rear wheels, 3 is a shaft torque meter, 4 is an output converter thereof, and 10 is a load command signal generating means. 7 differs from the configuration shown in FIG. 7 in that an output of the shaft torque meter 3 is provided between a constant velocity machine 1 and rollers 2 of front and rear wheels. After amplification and output level matching (sensitivity matching or coefficient processing) by the meter output converter 4, addition is performed on the front wheel side and the rear wheel side, and the output C is input to the load command signal generation means 10 .

The load command signal generating means 10 includes a differentiating means 11, a mechanical loss setting means (ML) 12, a running resistance setting means (RL) 13, a machine inertia detecting / calculating means 14, an inertia setting means 15, a subtracting means 16, and a multiplying means 17. 7 is different from the configuration shown in FIG. 7 in that the output of the mechanical inertia detecting / calculating means 14 and the output of the inertia setting means 15 are subtracted by the subtracting means 16 and then the multiplying means 17 is executed. And the output of the differentiating means 11 is multiplied. The output C from the shaft torque meter is input to the adding means 18, and the output of the running resistance setting means 13 is first added (subtracted) to the negative polarity.

The output of the shaft torque meter 3 is positive when the power flows from the rollers 2 of the front and rear wheels to the constant velocity machine 1. This is the same both before and after. In this case, the mechanical loss set in the mechanical loss setting means 12 may be measured with the constant velocity machine 1 separated, and the mechanical loss generated in the constant velocity machine 1 is not necessarily stable. You don't have to. Also, as already mentioned, even if the front and rear driving force distribution of the test vehicle changes and the loss inside the constant velocity machine increases accordingly, the sum of the outputs of the two shaft torque meters will The measurement will be automatically corrected due to internal losses.

In this embodiment, as in the conventional example, the output of the mechanical loss setting means (ML) 12 is not sent to the adding means 18 but the longitudinal power obtained from the load cell (LC) is indicated by a dotted line in FIG. There is also a method of adding to the total value of the braking force of the meter, and the same effect can be obtained in terms of control. In this case, the output C from the shaft torque meter is added to the addition result for the braking force as shown as output C 'instead of being input to the adding means 18.

 This embodiment has the following advantages.

(1) Using a constant-velocity machine prevents mechanical differences in the peripheral speeds of the front and rear wheel rollers, and completely compensates for the internal loss of the constant-velocity machine irrespective of changes in the front-rear driving force sharing of the test vehicle. As a result, the apparent resistance becomes zero, and the accuracy of the running resistance control is improved. Therefore, a highly accurate exhaust gas test and fuel consumption test can be performed.

(2) A constant-velocity machine generally has a large internal loss, and if the lubricating oil temperature control is not performed, the loss is unstable and the required warm-up time is long. However, in this embodiment, the lubricating oil temperature control is not required. It is not necessary to consider the warm-up time of the speed unit, and the operation is easily adjusted.
There is no need for a heater for lubricating oil.

(3) The inertia of the constant velocity machine is apparently zero, and the flexibility of the system configuration is improved.

FIG. 2 is a block diagram of another embodiment of the present invention, in which the same components as those in FIG. 1 are partially omitted.
In the figure, reference numeral 20 denotes a load command signal generating means. In the present embodiment, the accelerations of the roller peripheral speeds of the front wheels and the rear wheels are calculated by independent differentiating means 21 and 22, and the sum of them is input to the load command signal generating means 20 . Another difference of the present embodiment is that the mechanical loss setting means (ML) 23 and 24 are provided separately for the front and rear wheels. And the mechanical loss of the flywheel (the dynamometer loss is included in the load cell and output, so there is no need to set the mechanical loss setting means). The outputs of the mechanical loss setting means 23 and 24 are:
It is to be added to the output of the load cell for detecting the braking force generated by the front and rear wheel dynamometers, and the input to the load command signal generating means 20 has been released. The outputs of the other torque meters are also added to the output of the load cell (LC).

Therefore, the signals shown as F _CF and F _{CR in} FIG.
The dynamometer braking force of the front wheel or the rear wheel, the mechanical loss braking force of the rollers and the flywheel, and the braking force component flowing into the constant velocity machine are obtained. Therefore, F _DF , F _DR ; front wheel or rear wheel side dynamometer braking force F _MF , F _MR ; front wheel or rear wheel side roller and flywheel mechanical loss braking force F _FF , F _FR ; front wheel or rear wheel side torque meter Assuming output (all units are kg · f), F _CF = F _DF + F _MF + F _EF (1) F _CR = F _DR + F _MR + F _ER (2), and these F _CF and F _{The CR} is controlled so as to balance the running resistance command component and the electric inertia control command component output from the load command signal generating means 20.

In such a device, the driving force F _VF , F _VR (kg · f) of the test vehicle received by the front and rear wheel rollers is as follows.

F _VF = F _CF + I _MF / g · (d _VF / dt) …… (3) F _VR = F _CR + I _MR / g · (d _VR / dt)… (4) where I _MF , I _MR ; a gravitational acceleration (m / s ^2); mechanical like price inertial mass of the front or rear wheels _{(kg) V F, V R} ; front or rear wheels of the roller circumferential speed (m / s) g. Therefore, the second term on the right side of the above equations (3) and (4) may be calculated and added to the right sides of the above equations (1) and (2). The multipliers 25 and 26 in FIG.
Or to calculate each value of the above equation by the acceleration d _VF / dt or d _VR / dt output from 22 and each mechanical inertia value,
The output is added to the _FCF or _FCR . The measurement of the total generated driving force of the vehicle can be easily performed by providing a means (not shown) for calculating (F _VF + F _VR ).

 This embodiment has the following advantages.

(1) Since the sharing of the front and rear wheel driving forces of the test vehicle can be measured without mounting a wheel torque meter on the wheels of the vehicle, the test efficiency is improved and the behavior analysis of the vehicle can be easily performed.

(2) The accuracy of measuring the total driving force of the vehicle is improved. Although this was measurable in the past, it had the disadvantage that the mechanical loss inside the constant-speed machine was large, and the inertia behavior in the constant-speed machine caused the backlash of the clutch, bevel gear, coupling device and other parts.
Has been improved.

FIG. 3 is a configuration diagram of still another embodiment of the present invention. In the figure, 30 is a load command signal generating means, 31 is a constant speed machine, 32 is rollers for front and rear wheels, and 33 is a shaft torque meter. This embodiment shown in the figure is basically the same as the second embodiment, except that it comprises a calculating means 34 for calculating the output difference between the front and rear shaft torque meters, and its output D is used to distribute the dynamometer current. The difference is that the current is input to the unit 35 to change the current distribution.

In this embodiment, similarly to FIG. 1, instead of sending the output of the mechanical loss setting means (ML) 36 to the adding means 37, as shown by a dotted line in FIG. There is a method of adding to the total value of the braking force of the meter, and the same effect can be obtained in terms of braking. In this case, the output C from the shaft torque eater is not input to the adding means 37, but is added to the addition result for the braking force as the output C '.

 This embodiment has the following advantages.

(1) The capacity of the constant-velocity machine can be reduced to the minimum necessary value.

(2) Since the internal calorific value of the constant velocity machine is reduced on average, only the spontaneous heat is sufficient, and the lubricating oil cooling device is not required.

(3) There is no need to finely define the play amount of the constant velocity machine.

(4) For the above-mentioned reasons, the constant-speed machine becomes inexpensive.

Now, the distributor will be described. The ordinary distribution circuit is a semi-fixed coefficient circuit such that (K _F + K _R ) = 1 as shown in FIG. When the assignment is almost fixed, as shown in FIG. 4 (b), an assignment ratio setting device 41 may be provided to make the assignment variable. Further, when the dynamometer capacities of the front and rear wheels are different, the coefficient processing in consideration of the difference in the dynamometer capacities is performed in both FIGS. 4 (a) and 4 (b).

The distribution circuit used in the third embodiment is shown in FIG.
As shown in the figure, when the output difference ΔF between the front wheel torque meter 42 and the rear wheel torque meter 43 is positive, the braking force command of the front wheel dynamometer is increased, and when the output difference ΔF is negative, the braking force command of the front wheel dynamometer is increased. To increase. In this way, the braking force passing through the constant velocity machine is minimized, and the capacity of the constant velocity machine is reduced. However, the present invention is effective only when the capacity of the dynamometer is sufficiently large and only one of the dynamometers can absorb the driving force generated on the front wheel or the rear wheel. Further, even if the dynamometer does not have a sufficient capacity, the same effect can be obtained by setting the current / braking force conversion coefficient KI of the distribution circuit low.

Although the circuit of FIG. 2 and the circuit of FIG. 3 have some differences, they do not interfere with each other and can be executed simultaneously.

FIG. 5 is a graph of an operation test state by the new synchronous control method. The test vehicle is a viscous joint type 4WD vehicle, which is driven on the front / rear separation type chassis dynamometer of the present invention.
Within this range, very good results were obtained, and the following effects were evident.

(1) There is no need for a constant velocity machine which is expensive and requires a large space.

(2) Since loss does not occur in the constant velocity machine, highly accurate running resistance control is possible.

(3) The driving forces generated by the front and rear wheels can be independently measured.

H. Effects of the Invention As described above, according to the present invention, an expensive and large-sized constant-velocity machine is not required, and a high-precision running resistance control becomes possible because no loss occurs in the constant-velocity machine, It is possible to provide a chassis dynamometer control method for a four-wheel drive vehicle that can independently measure the driving forces generated by the front and rear wheels.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a block diagram of another embodiment of the present invention, FIG. 3 is a block diagram of still another embodiment of the present invention, FIG. Is an explanatory diagram of the distribution circuit of the embodiment, FIG. 5 is a graph of an operation state by the new synchronous control system, FIG. 6 is a configuration diagram for a 4WD vehicle test, and FIG. 7 is a configuration diagram of a conventional example. DESCRIPTION OF SYMBOLS 1 ... Constant velocity machine, 2 ... Roller of front wheel and rear wheel, 3 ... Shaft torque meter, 4 ... Shaft torque meter output converter, 10 ...
... Load command signal generating means, 11 Differentiating means, 12 Mechanical loss setting means, 13 Running resistance setting means, 14 Mechanical inertia detection / calculation means, 15 Inertia setting means, 16 Subtraction Means, 17 multiplication means, 18 addition means.

Claims (3)

(57) [Claims] 1. A constant velocity machine for connecting both shaft ends variably with a shaft center distance, rollers for front wheels and rear wheels, vehicle speed detecting means for detecting a rotation speed or a peripheral speed of the rollers, and each of the rollers is coupled to each roller. Power absorbing device, braking force detecting means for detecting the torque of the power absorbing device, dynamometer control device for independently controlling the power absorbing device, and running resistance setting means for setting the steady running resistance of the test vehicle as a vehicle speed function And a chassis mechanical dynamometer control system in which a load command signal based on the vehicle speed signals of the front wheels and the rear wheels is commanded by a distributor to the dynamometer control devices of the front wheels and the rear wheels. Shaft torque meters each disposed between two input shafts of the machine and shaft ends of chassis dynamometers for front wheels or rear wheels, and shaft torque meters for matching their outputs to predetermined electric outputs Out A chassis dynamometer control system for a four-wheel drive vehicle, comprising a force converter and an adder for summing the outputs of the two converters, and subtracting the output of the adder from a load command signal. 2. A load command signal, wherein a difference between a multiplied value of an average acceleration signal detected from the roller side of the chassis dynamometer and an output of the inertia setting means and a multiplied value of the average acceleration signal and the output of the mechanical inertia detection calculating means is calculated. The four-wheel-drive vehicle chassis dynamometer control method according to claim 1, wherein the value is subtracted from the following. 3. A dynamometer control device for performing a torque control by branching and inputting a signal output from a control force detecting means is connected to a distributor, and a load command signal is directly input to the distributor. The chassis dynamometer control system for a four-wheel drive vehicle according to claim (1).