JP2021139778A - Vehicle diagnosing device - Google Patents

Abstract

To precisely determine the degree of degradation in a suspension device.SOLUTION: The present invention relates to a vehicle diagnosing device for diagnosing a vehicle, having a suspension device attached between a vehicle and a driving wheel. The vehicle diagnosing device determines the level of the degree in the suspension device on the basis of the wheel rate of the vehicle, the longitudinal acceleration of the vehicle, and the wheel angle of the vehicle. In that way, the present invention can determine the level of the degree in the suspension device more accurately than a device for determining the degradation in the suspension device on the basis of the frequency of the wheel rate from a wheel rate sensor alone.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle diagnostic device, and more particularly to a vehicle diagnostic device that diagnoses a vehicle including a suspension device having a shock absorber.

Conventionally, as a diagnostic device for this type of vehicle, a device for diagnosing a vehicle including a suspension device has been proposed (see, for example, Patent Document 1). In this device, the resonance frequency under the vehicle body unsprung is calculated based on the frequency of the wheel speed from the wheel speed sensor. Then, the spring constant under the vehicle body spring is calculated from the calculated resonance frequency. Further, it is determined whether or not the suspension device is deteriorated based on the calculated spring constant and the tire pressure.

Japanese Unexamined Patent Publication No. 2000-318416

In the above-mentioned vehicle diagnostic device, when it is determined whether or not the suspension device is deteriorated while the vehicle is accelerating / decelerating or turning, the frequency of the wheel speed changes depending on the acceleration / deceleration or turning of the vehicle. Therefore, the resonance frequency cannot be calculated properly. Therefore, it may not be possible to accurately determine the degree of deterioration of the suspension device.

The main object of the vehicle diagnostic device of the present invention is to accurately determine the degree of deterioration of the suspension device.

The vehicle diagnostic device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The vehicle diagnostic device of the present invention
A vehicle diagnostic device that diagnoses a vehicle equipped with a suspension device mounted between the vehicle body and the drive wheels.
The gist is to determine the degree of deterioration of the suspension device based on the wheel speed of the vehicle, the front-rear acceleration of the vehicle, and the steering angle of the vehicle.

In the vehicle diagnostic device of the present invention, the degree of deterioration of the suspension device is determined based on the wheel speed of the vehicle, the front-rear acceleration of the vehicle, and the steering angle of the vehicle. As a result, the degree of deterioration of the suspension device can be determined more accurately than the one that determines the deterioration of the suspension device based on the frequency of the wheel speed from the wheel speed sensor.

In such a vehicle diagnostic device of the present invention, the suspension device includes a shock absorber, and a band pass filter process in which the frequency of the shaking of the vehicle body is set as a passing band with respect to a time change of the wheel speed in a predetermined processing period. To generate a waveform of the wheel speed after processing, and to perform the bandpass filter processing on the time change of the front-rear acceleration and the front-rear acceleration in the predetermined processing period, and to generate the waveform of the front-rear acceleration after processing. , And, using the steering angle, a determination period in which the fluctuation of the wheel speed due to acceleration / deceleration or turning of the vehicle is within an allowable range is set, and the peak value of the waveform of the processed wheel speed in the determination period is set. The degree of deterioration of the suspension device may be determined from the decrease in the damping force of the shock absorber based on the change. Since the determination period is set in consideration of the front-rear acceleration, the front-rear acceleration after processing, and the steering angle, the degree of deterioration of the suspension device can be judged more appropriately.

In this case, the determination period includes a condition that the absolute value of the anteroposterior acceleration is less than a predetermined acceleration, a condition that the absolute value of the post-processing anteroposterior acceleration is less than a predetermined fluctuation in the waveform of the post-processing anteroposterior acceleration, and a condition. , The period in which all the conditions under which the absolute value of the steering angle is less than a predetermined angle is satisfied may be set. By doing so, the period in which the fluctuation of the wheel speed due to the front-rear acceleration, the post-processing front-rear acceleration, and the steering angle is small can be set as the determination period, and the determination period can be made more appropriate.

Further, in this case, the determination period is a condition that the absolute value of the front-back acceleration is less than a predetermined acceleration, and a condition that the absolute value of the front-back acceleration after processing is less than a predetermined fluctuation in the waveform of the front-back acceleration after processing. , And the condition that the absolute value of the steering angle is less than the predetermined angle and the condition that the vehicle speed is equal to or more than the predetermined speed may be set as a period.

In this case, the degree of deterioration of the suspension device is the next peak following the first peak value whose absolute value is equal to or greater than a predetermined value among the plurality of peak values of the waveform of the processed wheel speed in the determination period. The determination may be made based on the ratio of the absolute value of the third peak value to the absolute value of the first peak value. In this case, the degree of deterioration of the suspension device is the ratio of the absolute value of the third peak value to the absolute value of the first peak value, and the absolute value of the third peak value and the first peak value. The determination may be made based on the ratio of the second peak value to the absolute value, which is the next peak value of.

It is a block diagram which shows the outline of the structure of the vehicle diagnosis system 10 including the vehicle diagnosis device as one Example of this invention. It is a flowchart which shows an example of the processing routine executed by the computer 21 of the management center 20. It is explanatory drawing which shows an example of the period which satisfies the condition that the absolute value | Wαf | of the post-processing acceleration Wαf | is less than a predetermined value Wαfref. It is explanatory drawing which shows an example of the peak value P1 to P3 of the waveform of the wheel speed Wvwf after processing. It is a flowchart which shows an example of the processing routine of a modification.

Next, a mode for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of a vehicle diagnostic system 10 including a vehicle diagnostic device as an embodiment of the present invention. The vehicle diagnostic system 10 includes a management center 20 and a vehicle 30 as shown in the figure. In the embodiment, the computer 21 of the management center 20 corresponds to the “vehicle diagnostic device”.

The management center 20 includes a computer 21, a storage device 22, and a communication device 23 that are connected to each other via a signal line. The computer 21 has a CPU, a ROM, a RAM, an input / output port, a communication port, and the like. The storage device 22 is configured as, for example, a hard disk, an SSD, or the like. Data related to the vehicle 30 and the like are stored in the storage device 22. The communication device 23 communicates between the computer 21 and the outside.

The vehicle 30 is configured as a front-wheel drive vehicle, and as shown in the figure, the vehicle 30 includes a power source 32, drive wheels 30a and 30b as front wheels, driven wheels 30c and 30d as rear wheels, a vehicle body 38, and a suspension device 40a. ~ 40d, an electronic control unit (hereinafter referred to as “ECU”) 50, and a communication device 52.

The power source 32 is configured to output power for traveling, such as a motor or an engine, to a drive shaft 36 connected to the drive wheels 30a and 30b via a differential gear 35. The power source 32 is controlled by the ECU 50.

The suspension devices 40a to 40d are mounted between the driving wheels 30a and 30b and the driven wheels 30c and 30d and the vehicle body 38, and are configured as a well-known suspension device that alleviates the impact transmitted from the road surface to the vehicle body 38. It has an arm, a spring, and shock absorbers (dampers) 42a to 42d. The shock absorbers 42a to 42d are configured as well-known double-cylinder or single-cylinder shock absorbers having a cylinder, a piston (piston valve), a piston rod, and hydraulic oil (oil), respectively. , It has an outer tube (outer cylinder), a base valve, and gas, and in the case of a single cylinder type, it has a free piston and high pressure gas.

Although not shown, the ECU 50 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. ..

Signals from various sensors are input to the ECU 50. Examples of the signal input to the ECU 50 include a detection signal from a sensor for detecting the state of the power source 32. The wheel speeds Vw1 to Vw4 from the wheel speed sensors 31a to 31d that detect the wheel speeds of the driving wheels 30a and 30b and the driven wheels 30c and 30d can also be mentioned. The ignition signal from the ignition switch 60 and the shift position SP from the shift position sensor 62 that detects the operation position of the shift lever 61 can also be mentioned. Examples include the accelerator opening Acc from the accelerator pedal position sensor 64 that detects the amount of depression of the accelerator pedal 63, and the brake pedal position BP from the brake pedal position sensor 66 that detects the amount of depression of the brake pedal 65. Examples include the front-rear acceleration α from the acceleration sensor 70 that detects acceleration in the front-rear direction and the steering angle θ from the steering angle sensor 72 that detects the steering angle of the steering wheel (not shown).

Various control signals are output from the ECU 50 via the output port. Examples of the signal output from the ECU 50 include a control signal for controlling the power source 32. The ECU 50 executes various calculations for driving the vehicle 30. The ECU 50 calculates the vehicle speed V based on the wheel speeds Vw1 to Vw4 from the wheel speed sensors 31a to 31d.

The communication device 52 communicates between the ECU 50 and the outside.

In the vehicle 30 of the embodiment, the ECU 50 controls the power source 32 so as to travel based on the required load factor and the required power. While traveling, the ECU 50 sequentially transmits various data to the management center 20 via the communication device 52. Examples of the data transmitted from the ECU 50 include wheel speeds Vw1 to Vw4 detected by the wheel speed sensors 31a to 31d, front-rear acceleration α detected by the acceleration sensor 70, steering angle θ detected by the steering angle sensor 72, and the like. be able to.

In the vehicle diagnosis system 10 configured in this way, the communication device 23 of the management center 20 receives various data (for example, wheel speeds Vw1 to Vw4, vehicle speed V, front-rear acceleration α, steering angle θ) transmitted from the vehicle 30. Is output to the storage device 22. The storage device 22 stores various input data and holds it for a predetermined storage period (for example, 5 years, 7 years, 10 years, etc.). The computer 21 of the management center 20 diagnoses various states of the vehicle 30 based on various data of the vehicle 30 stored in the storage device 22.

Next, the operation of the vehicle diagnosis system 10 thus configured, particularly the operation of diagnosing the degree of deterioration of the suspension device 40a at the management center 20 will be described. FIG. 2 is a flowchart showing an example of a processing routine executed by the computer 21 of the management center 20. This routine is executed when a service request signal requesting the diagnostic service of the vehicle 30 is input to the computer 21 via the communication device 23 of the management center 20. Here, the service request signal is transmitted from the diagnostic facility when a computer or the like (not shown) of the diagnostic facility receives an instruction to execute the diagnostic service of the vehicle 30 by the staff of the diagnostic facility (not shown) requesting the diagnostic service of the vehicle 30. NS. Examples of the diagnostic facility include factories and dealers that inspect and trade in the vehicle 30, and service shops that receive requests for diagnosis of the vehicle 30 from such factories and dealers. In the embodiment, the degree of deterioration of the suspension device 40a is diagnosed, but by applying the same processing to the suspension devices 40b to 40d, the degree of deterioration of the suspension devices 40b to 40d can be diagnosed.

When this routine is executed, the computer 21 of the management center 20 has the wheel speed input by the storage device 22 within the Pstep (for example, 1 hour, 1.5 hours, 2 hours, etc.) via the communication device 23. Input Vw1 data (hereinafter referred to as "wheel speed data") Dw1, front-rear acceleration α data (hereinafter referred to as "front-rear acceleration data") Dα, and steering angle θ data (hereinafter referred to as "steering angle data") Dθ. (Step S100).

Subsequently, bandpass processing is applied to the wheel speed data Dw1 and the front-rear acceleration data Dα to generate a waveform of the processed wheel speed Wvwf and a waveform of the processed acceleration Wαf (step S110). In the bandpass processing, a frequency (for example, 0.5 Hz to 2 Hz, etc.) predetermined by experiments or analysis is set as the pass band as the frequency of the shaking generated in the vehicle body 38 during traveling due to the unevenness of the road surface.

Next, the determination period Pj is set (step S120). The determination period Pj is a condition in which the vehicle speed V is equal to or higher than the predetermined vehicle speed Vref, a condition in which the absolute value | α | of the front-rear acceleration α is less than the predetermined acceleration αref (positive value), and the absolute value of the processed acceleration Wαf. During the period in which all of the conditions in which | Wαf | is less than the predetermined value Wαfref (positive value) and the absolute value of the steering angle θ | θ | is less than the predetermined angle θref (positive value) are satisfied. be. Here, the predetermined vehicle speed Vref is a threshold value for determining whether or not the shaking of the vehicle body 38 that occurs immediately after the start of the vehicle due to the start of the vehicle is sufficiently small, and is set to, for example, 10 km / h. NS. The predetermined acceleration αref is a threshold value for determining whether or not the shaking of the vehicle body 38 due to acceleration / deceleration of the vehicle is sufficiently small, and is set to ^{, for example, 1.5 m / s 2.} The predetermined value Wαfref is a threshold value for determining whether or not the post-processing acceleration Wαf, that is, whether or not the shaking of the vehicle body 38 due to the fluctuation of the front-rear acceleration α is sufficiently small, for example, 0.12 m / s ^2. , 0.16 m / s ^{2 and the} like. The predetermined angle θref is a threshold value for determining whether or not the shaking of the vehicle body 38 due to turning is sufficiently small, and is set to, for example, 5 degrees. FIG. 3 is an explanatory diagram showing an example of a period in which the absolute value | Wαf | of the processed acceleration Wαf | is less than the predetermined value Wαfref. Therefore, in the determination period Pj, the fluctuation of the wheel speed Vw1 due to the shaking of the vehicle body 38 caused by the start, acceleration / deceleration, and turning of the vehicle 30 is sufficiently small, and the shaking of the vehicle body 38 is mainly caused by the unevenness of the road surface. Set as a period.

When the determination period Pj is set in this way, next, the peak values P1 to P3 of the waveform of the processed wheel speed Wvwf in the determination period Pj are extracted (step S130). FIG. 4 is an explanatory diagram showing an example of peak values P1 to P3 of the waveform of the processed wheel speed Wvwf. As for the peak values P1 to P3, as shown in FIG. 4, the one whose absolute value is equal to or higher than the threshold value Wvwref is defined as the peak value P1, the peak value next to the peak value P1 is defined as the peak value P2, and the peak value next to the peak value P2 is defined. Is the peak value P3, and the absolute values of the peak values P1, P2, and P3 | P1 |, | P2 |, | P3 | satisfy the relationship (| P1 |> | P2 |> | P3 |). Set as a thing.

Next, the peak ratio R1 (= | P3 | / | P1 |), which is the ratio of the absolute value | P3 | of the peak value P3 and the absolute value | P1 | of the peak value P1, and the absolute value of the peak value P3 | P3 | And the peak ratio R2 (= | P3 | / | P2 |), which is the ratio of the peak value P2 to the absolute value | P2 |, is calculated (step S140).

Then, the degree of deterioration of the suspension device 40a is determined using the peak ratios R1 and R2 (step S150), and this routine is terminated. In this determination, when the peak ratios R1 and R2 are large, it is determined that the deterioration is progressing as compared with when the peak ratios R1 and R2 are small. When the damping force of the shock absorber 42a is reduced, it becomes difficult to alleviate the impact transmitted from the road surface to the vehicle body 38, and the time required to sufficiently reduce the shaking of the vehicle body 38 becomes long. Therefore, it takes time for the magnitude of fluctuation of the wheel speed Vw1, that is, the peak values P1 to P3 of the waveform of the wheel speed Wvwf after processing to become small. Therefore, when the deterioration of the suspension device 40a is progressing, the peak ratios R1 and R2 become larger than when the deterioration is not progressing. Therefore, the shock absorber can be examined by examining the changes in the peak ratios R1 and R2. The degree of deterioration of the suspension device 40a due to the decrease in the damping force of the 42a can be determined. Since the peak ratios R1 and R2 are the determination period Pj, that is, the peak ratio during the period in which the shaking of the vehicle body 38 is mainly caused by the unevenness of the road surface, the deterioration of the suspension device 40a by examining the peak ratios R1 and R2. Can be accurately determined.

According to the vehicle diagnosis system 10 including the vehicle diagnosis device of the embodiment described above, the suspension device is based on the wheel speeds Vw1 to Vw4 of the vehicle 30, the front-rear acceleration α of the vehicle 30, and the steering angle θ of the vehicle 30. Since the degree of deterioration of the suspension devices 40a to 40d is determined, the degree of deterioration of the suspension devices 40a to 40d can be accurately determined.

In the vehicle diagnosis system 10 including the vehicle diagnosis device of the embodiment, the processing routine illustrated in FIG. 2 is executed by the computer 21 of the management center 20. However, instead of the processing routine illustrated in FIG. 2, the processing routine of the modified example illustrated in FIG. 5 may be executed. The processing routine of the modified example of FIG. 5 is different from the processing routine of FIG. 2 except that steps S200 and S210 are executed without executing step S110 between steps S100 and S120 of the processing routine of FIG. Perform the same process. Therefore, in the description of the modified example processing routine of FIG. 5, the same processing as that of the processing routine of FIG. 2 is designated by the same reference numerals, and the description thereof will be omitted.

When the computer 21 of the management center 20 inputs the wheel speed data Dw1, the front-rear acceleration data Dα, and the steering angle data Dθ in step S100, the computer 21 sets the filter processing period Pf when performing the filter processing in step S220 described later (step). S200). The filter processing period Pf is determined by the condition that the vehicle speed V is equal to or higher than the predetermined vehicle speed Vref, the condition that the absolute value | α | of the front-rear acceleration α is less than the predetermined acceleration αref, and the absolute value | θ | of the steering angle θ. It is a period in which all the conditions that the angle is less than θref are satisfied. The predetermined vehicle speed Vref, the predetermined acceleration αref, and the predetermined angle θref are the same values as those used in the process of step S120 of the process routine of FIG. Therefore, the determination period Pj is set as a period during which the shaking of the vehicle body 38 due to the starting or acceleration / deceleration of the vehicle 30 is sufficiently small.

When the filter processing period Pf is set in this way, the wheel speed data Dw1 and the front-rear acceleration data Dα in the filter processing period Pf are subjected to bandpass processing to generate a waveform of the processed wheel speed Wvwf and a waveform of the processed acceleration Wαf ( Step S210). Similar to step S110 of the processing routine of FIG. 2, the bandpass processing in step S210 is a frequency determined in advance by experiments, analysis, or the like as the frequency of shaking generated in the vehicle body 38 during traveling due to the unevenness of the road surface (for example,). The pass band is 0.5 Hz to 2 Hz, etc.).

When the bandpass filter processing is executed in this way, the processing after step S120 is executed to end this routine. Thereby, the degree of deterioration of the suspension devices 40a to 40d can be accurately determined.

In the vehicle diagnosis system 10 including the vehicle diagnosis device of the embodiment, the peak values P1 to P3 of the waveform of the processed wheel speed Wvwf in the determination period Pj are extracted in step S130. However, the number of peak values to be extracted is not limited to three, and may be a plurality. For example, when the number of peak values to be extracted is four, four peak values (for example, the peak value P4 following the peak values P1, P2, P3, and the peak value P3) are extracted in step S130, and steps S140 and S150 are used. Then, the peak ratio R3 (= | P4 | /), which is the ratio of the peak ratio R1 (= | P3 | / | P1 |) to the absolute value | P4 | of the peak value P4 and the absolute value | P2 | of the peak value P2. | P2 |) may be used to determine the degree of deterioration of the suspension device 40a. In this case, the degree of deterioration of the suspension device 40a may be determined by determining that the deterioration of the suspension device 40a is larger when the peak ratio R1 or R3 is large than when it is small.

In the vehicle diagnosis system 10 including the vehicle diagnosis device of the embodiment, the processing routines of the examples and modifications of FIGS. 2 and 5 are executed by the computer 21 of the management center 20. However, a part or all of the processing routines of the examples and modifications of FIGS. 2 and 5 may be executed by the ECU 50 of the vehicle 30.

The correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the suspension devices 40a to 40d correspond to the "suspension device", and the computer 21 of the management center 20 corresponds to the "vehicle diagnostic device".

Regarding the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problem in the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to examples, the present invention is not limited to these examples, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the manufacturing industry of vehicle diagnostic devices and the like.

10 vehicle diagnostic system, 20 management center, 21 computer, 22 storage device, 23 communication device, 30 vehicle, 32 power source, 30a, 30b drive wheel, 30c, 30d driven wheel, 31a to 31d wheel speed sensor, 35 differential gear, 36 Drive shaft, 38 Body, 40a-40d Suspension device, 42a-42d Shock absorber, 50 Electronic control unit (ECU), 52 Communication device, 60 Ignition switch, 61 Shift lever, 62 Shift position sensor, 63 Accelerator pedal, 64 Accelerator Pedal position sensor, 65 brake pedal, 66 brake pedal position sensor, 70 acceleration sensor, 72 steering angle sensor.

Claims (1)

A vehicle diagnostic device that diagnoses a vehicle equipped with a suspension device mounted between the vehicle body and the drive wheels.
A vehicle diagnostic device that determines the degree of deterioration of the suspension device based on the wheel speed of the vehicle, the front-rear acceleration of the vehicle, and the steering angle of the vehicle.

Images