CN117549844A - Transfer case coil diagnosis method, system and vehicle - Google Patents

Abstract

The invention provides a transfer case coil diagnosis method, a transfer case coil diagnosis system and a vehicle, wherein coil information of a transfer case coil is acquired, and whether the transfer case coil meets preset running conditions is judged according to the coil information; if the transfer case coil meets the preset operation condition, acquiring a first duty ratio of the transfer case coil; judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio; if the transfer case coil meets the coil open circuit diagnosis condition, and the first coil current of the transfer case coil is smaller than the preset current, counting a first duration time when the first coil current is smaller than the preset current; and if the first duration is longer than the first preset duration, determining that the transfer case coil has an open circuit fault.

Description

Transfer case coil diagnosis method, system and vehicle

Technical Field

The invention relates to the technical field of four-wheel drive vehicles, in particular to a transfer case coil diagnosis method, a transfer case coil diagnosis system and a vehicle.

Background

The timely transfer case is an important transmission part in a longitudinally-arranged four-wheel drive vehicle, realizes a four-wheel drive function of the vehicle by outputting the input torque of the transmission to the front axle and the rear axle, specifically, controls the magnitude of current in an internal transfer case coil through the slip rate of wheels, and adjusts the compression degree of an internal friction plate according to the magnitude of the current in the transfer case coil so as to intelligently distribute the torque output by the timely transfer case to the front axle and the rear axle. It follows that control of the magnitude of the transfer case coil current is critical to achieving intelligent torque distribution.

The current of the transfer case coil is mainly realized by a four-wheel drive controller through controlling PWM (duty cycle). The four-wheel drive controller is used for controlling the current of the transfer case coil and simultaneously carrying out fault diagnosis on the transfer case coil; among them, the most common fault diagnosis is the diagnosis of open circuit faults of the transfer case coil.

In the prior art, the four-wheel drive control unit can diagnose whether the transfer case coil has open-circuit faults or not according to a preset transfer case coil open-circuit fault strategy; however, under the existing open-circuit fault strategy, when the voltage supplied by the four-wheel drive controller changes, the system is easy to misreport the open-circuit fault of the transfer case coil, and the vehicle is easy to lose the four-wheel drive function.

Disclosure of Invention

In view of the above, the present invention provides a method, a system and a vehicle for diagnosing a transfer case coil, which aim to prevent the system from misreporting an open circuit fault of the transfer case coil, resulting in the vehicle losing the four-wheel drive function.

A first aspect of the invention provides a transfer case coil diagnostic method comprising:

acquiring coil information of a transfer case coil, and judging whether the transfer case coil meets preset running conditions according to the coil information;

If the transfer case coil meets the preset running condition, acquiring a first duty ratio of the transfer case coil;

judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio;

if the transfer case coil meets the coil open circuit diagnosis condition, and the first coil current of the transfer case coil is smaller than a preset current, counting a first duration time that the first coil current is smaller than the preset current;

and if the first duration is longer than the first preset duration, determining that the transfer case coil has an open circuit fault.

Optionally, the method further comprises:

detecting whether the second duty cycle of the transfer case coil is a second preset duty cycle when the power-on of the vehicle is detected;

if the second duty cycle is the second preset duty cycle, collecting second coil current of the transfer case coil;

if the second coil current is smaller than the preset current, counting a second duration time when the second coil current is smaller than the preset current, and judging whether the second duration time is larger than a second preset duration time or not;

and if the second duration is not greater than the second preset duration, determining that the vehicle is complete to power on self-test, and executing the step of acquiring coil information of the transfer case coil.

Optionally, the method further comprises:

and if the second duration is longer than the second preset duration, determining that the transfer case coil has an open circuit fault.

Optionally, the acquiring the coil information of the transfer case coil, and determining whether the transfer case coil meets a preset operation condition according to the coil information includes:

acquiring coil information of a transfer case coil; wherein the coil information includes a temperature of the transfer case coil and/or a transfer case coil resistance;

judging whether the temperature of the transfer case coil is greater than a target temperature threshold value and/or whether the resistance of the transfer case coil is greater than a maximum coil resistance value;

if the temperature of the transfer case coil is not greater than the target temperature threshold value and/or the resistance of the transfer case coil is not greater than the maximum coil resistance, determining that the transfer case coil meets the preset running condition;

and if the temperature of the transfer case coil is greater than the target temperature threshold value and/or the resistance value of the transfer case coil is greater than the maximum coil resistance value, determining that the transfer case coil does not meet the preset running condition.

Optionally, the determining, according to the first duty cycle, whether the transfer case coil meets a coil open circuit diagnosis condition includes:

Judging whether the first duty cycle is smaller than a first preset duty cycle or not; wherein the first preset duty cycle is determined according to the target temperature threshold and a preset output minimum voltage;

if the first duty cycle is smaller than the first preset duty cycle, determining that the transfer case coil does not meet a coil open circuit diagnosis condition;

and if the first duty ratio is not smaller than the first preset duty ratio, determining that the transfer case coil meets the coil open circuit diagnosis condition.

Optionally, the determining the first preset duty cycle according to the target temperature threshold and a preset output minimum voltage includes:

determining the maximum coil resistance value matched with the target temperature threshold value;

and determining the first preset duty ratio according to a preset output minimum voltage, the maximum coil resistance, a preset coil open-circuit threshold value and a preset coil open-circuit difference value.

Optionally, the determining the first preset duty cycle according to the preset output minimum voltage, the maximum coil resistance, the preset coil open-circuit threshold value and the preset coil open-circuit difference value includes:

adding a preset coil open-circuit threshold value and the preset coil open-circuit difference value to obtain a corresponding sum value;

Multiplying the maximum coil resistance by the sum to obtain a corresponding product;

and calculating the first preset duty cycle according to the product and the preset output minimum voltage.

Optionally, after determining that the transfer case coil has failed in an open circuit, the method further comprises:

and generating corresponding open-circuit fault information of the transfer case coil, and outputting the open-circuit fault information.

A second aspect of the invention provides a transfer case coil diagnostic system, the system comprising:

the first judging unit is used for acquiring coil information of the transfer case coil and judging whether the transfer case coil meets preset running conditions or not according to the coil information;

a first acquisition unit for acquiring a first duty cycle of the transfer case coil if the transfer case coil meets the preset operating condition;

the second judging unit is used for judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio;

the first statistical unit is used for counting a first duration time when the first coil current of the transfer case coil is smaller than the preset current if the transfer case coil meets the coil open circuit diagnosis condition;

And the first determining unit is used for determining that the transfer case coil has an open circuit fault if the first duration is longer than the first preset duration.

A third aspect of the invention provides a vehicle comprising a four-wheel drive controller for performing the transfer case coil diagnostic method provided by the first aspect of the invention.

The invention provides a transfer case coil diagnosis method, a transfer case coil diagnosis system and a vehicle, wherein coil information of a transfer case coil is acquired, and whether the transfer case coil meets preset running conditions is judged according to the coil information; when the transfer case coil meets a preset operation condition, acquiring a first duty ratio of the transfer case coil; judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio; if the transfer case coil meets the coil open circuit diagnosis condition, and the first coil current of the transfer case coil is smaller than the preset current, counting a first duration time when the first coil current is smaller than the preset current; and if the first duration is longer than the first preset duration, determining that the transfer case coil has an open circuit fault. According to the technical scheme provided by the invention, whether the transfer case coil meets the coil open circuit diagnosis condition can be judged according to the first duty ratio of the transfer case coil; if the coil open circuit diagnostic condition is met, determining whether an open circuit fault has occurred in the transfer case coil based further on the first coil current of the transfer case coil; if the coil open-circuit diagnosis condition is not met, whether the transfer case coil has an open-circuit fault is not required to be continuously judged, so that whether the transfer case coil has the open-circuit fault is judged according to the first coil current of the transfer case coil only when the coil open-circuit diagnosis condition is met, the situation that the system mistakenly reports the open-circuit fault of the transfer case coil to cause the vehicle to lose four driving forces can be effectively avoided, and the transfer case coil of the vehicle can be effectively detected by the four-wheel drive controller when the transfer case coil of the vehicle has the open-circuit fault indeed, so that the running reliability of the vehicle is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is an exemplary plot of duty cycle of a transfer case coil as a function of current of the transfer case coil as provided by the prior art;

FIG. 2 is a flow chart of a method for diagnosing a transfer case coil according to an embodiment of the present invention;

FIG. 3 is a flowchart of a method for detecting whether a power-on self-test of a vehicle is completed according to an embodiment of the present invention;

FIG. 4 is an exemplary plot of duty cycle of a transfer case coil as a function of current of the transfer case coil provided by an embodiment of the present invention;

FIG. 5 is an exemplary diagram of a transfer case coil diagnostic method provided in an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a transfer case diagnostic system according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The term "including" and variations thereof as used herein are intended to be open-ended, i.e., including, but not limited to. The term "based on" is based at least in part on. The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments. Related definitions of other terms will be given in the description below.

It should be noted that the terms "first," "second," and the like in this disclosure are merely used for distinguishing between different devices, modules, or units and not for limiting the order or interdependence of the functions performed by these devices, modules, or units.

It should be noted that references to "one" or "a plurality" in this disclosure are intended to be illustrative rather than limiting, and those of ordinary skill in the art will appreciate that "one or more" is intended to be interpreted as "one or more" unless the context clearly indicates otherwise.

As known from the above background art, in the prior art, a four-wheel drive controller of a vehicle may diagnose whether an open circuit fault occurs in a transfer case coil according to a preset open circuit fault strategy of the transfer case coil; specifically, the working voltage of the vehicle demand controller is 9-16V, and the voltage measured value of the vehicle supply controller is about 13.5V at the moment because the transfer case coil works under the starting working condition of the vehicle engine, and the resistance value of the transfer case coil is 2.5 ohms at normal temperature. Open circuit fault strategies based on which the transfer case coil is made may be: when the driving duty ratio of the transfer case coil is 5% or more, the transfer case coil open diagnosis is performed in real time, the coil open threshold is set to 0.2A, and the fault maturation time (debounce time) is set to 200ms.

Specifically, referring to fig. 1, as can be seen from fig. 1, the transfer case coil open fault strategy may specifically be: (1) at a duty cycle of 5%, the current value i=0.27a in the transfer case coil, and the coil open circuit threshold difference Δt=0.07A; (2) at a duty cycle of 10%, the current value i=0.54a in the transfer case coil, and the coil open circuit threshold difference Δt=0.34A; (3) at 13% duty cycle, the current value i=0.70a in the transfer case coil is different from the coil open threshold value Δt=0.50A.

As can be seen from the open fault strategy of the transfer case coil, the fault maturation (debounce) time is short due to the small delta T margin in the 5% -10% duty cycle region. When the supply voltage of the four-wheel drive controller changes, the system is easy to report the open circuit fault of the transfer case coil by mistake, and therefore the vehicle loses the four-wheel drive function.

Therefore, the embodiment of the invention provides a transfer case coil diagnosis method, a transfer case coil diagnosis system and a vehicle, wherein whether the transfer case coil meets a coil open circuit diagnosis condition is judged according to a first duty ratio of the transfer case coil; if the coil open circuit diagnostic condition is met, determining whether an open circuit fault has occurred in the transfer case coil based further on the first coil current of the transfer case coil; if the coil open-circuit diagnosis condition is not met, whether the transfer case coil has an open-circuit fault is not required to be continuously judged, so that whether the transfer case coil has the open-circuit fault is judged according to the first coil current of the transfer case coil only when the coil open-circuit diagnosis condition is met, the situation that the system mistakenly reports the open-circuit fault of the transfer case coil to cause the vehicle to lose four driving forces can be effectively avoided, and the transfer case coil of the vehicle can be effectively detected by the four-wheel drive controller when the transfer case coil of the vehicle has the open-circuit fault indeed, so that the running reliability of the vehicle is ensured.

Referring to fig. 2, a flow chart of a transfer case coil diagnosis method provided by the embodiment of the invention is shown, the transfer case coil diagnosis method is applied to a four-wheel drive controller on a vehicle, a timely transfer case is also installed on the vehicle, the timely transfer case comprises a transfer case coil, and the transfer case coil diagnosis method specifically comprises the following steps:

s201: coil information of the transfer case coil is acquired.

In the embodiment of the application, in order to ensure the safety of the vehicle in the running process, before the coil information of the transfer case coil is acquired, the vehicle can be subjected to power-on self-test when the vehicle is powered on, and the coil information of the transfer case coil of the vehicle is further acquired only under the condition that the power-on self-test of the vehicle is successfully completed. The coil information of the transfer case coil may include a temperature of the transfer case coil, a resistance value of the transfer case coil, and the like, and the embodiment of the present invention is not limited herein.

Referring to fig. 3, a flow chart of a method for detecting whether a vehicle power-on self-test is completed is shown, which specifically includes the following steps:

s301: when the power-on of the vehicle is detected, judging whether the second duty ratio of the transfer case coil is a second preset duty ratio or not; if the second duty cycle of the transfer case coil is the second preset duty cycle, step S302 is performed.

In the embodiment of the invention, the applicant researches show that after the vehicle is electrified, the power-on self-test of the vehicle is required to be completed in the shortest time possible, the power-on self-test completion time of the vehicle is shortened, and the duty ratio of the transfer case coil can be set to be the largest, namely, the duty ratio of the transfer case coil when the vehicle is electrified is defined as 100%, so that the purpose of shortening the power-on self-test completion time of the vehicle is achieved. Therefore, in order to shorten the power-on self-test completion time of the vehicle, the second preset duty ratio may be set to 100%, and the specific setting manner of the second preset duty ratio may be set according to the actual application, which is not limited in the embodiments of the present invention.

For example, the second preset duty ratio is set to 100% in advance; when it is detected that the vehicle is powered on, it may be detected whether the duty cycle of the power-on-time resolver coil of the vehicle (for convenience of distinction, the duty cycle of the power-on-time resolver coil of the vehicle is referred to as a second duty cycle) is equal to 100%; if the second duty cycle is equal to 100%, which indicates that the transfer case coil at this time meets the running condition of the vehicle, the coil current of the transfer case coil may be further detected, that is, step S302 is performed; if the speed of the transfer case coil is not equal to 100%, the transfer case coil at the moment is not required to meet the running condition of the vehicle, and corresponding prompt information can be output so as to prompt a user to perform corresponding inspection on the transfer case coil in time.

S302: and under the condition that the second duty ratio is a second preset duty ratio, collecting second coil current of the transfer case coil, and judging whether the second coil current is smaller than the preset current. If the second coil current is less than the preset current, step S303 is performed.

In the embodiment of the invention, the applicant researches show that after the vehicle is electrified, the power-on self-test of the vehicle is required to be completed in the shortest time as possible, the power-on self-test process of the vehicle is shortened, and the duty ratio of the transfer case coil can be set to be 100%; however, when the duty cycle of the transfer case coil is equal to 100%, the coil current of the transfer case coil increases. In order to ensure the normal operation of the transfer case coil, it is necessary to ensure that the duration that the coil current of the transfer case coil is less than the preset current is not too long, that is, in the time of powering up the vehicle for self-checking, it is necessary to ensure that the coil current of the transfer case coil gradually approaches the preset current and finally is greater than the preset current.

It should be noted that, according to the coil current requirement of the transfer case coil, the preset current may be set to 0.1A, and may be set according to practical applications, which is not limited in the embodiments of the present invention herein.

In the specific execution of step S302, when it is determined that the second duty cycle of the transfer case coil is the second preset duty cycle when the vehicle is powered on, the coil current of the transfer case coil may be further collected (for convenience of distinction, the collected coil current limit is referred to as the second coil current) and it is determined whether the second coil current is smaller than the preset current; if the second coil current is not smaller than the preset current, the open-circuit fault of the transfer case coil can be determined, corresponding open-circuit fault information of the transfer case coil can be generated, and the open-circuit fault information is output.

If the second coil current is smaller than the preset current, indicating that the second coil current is within the stable range, it may be further determined whether the second coil current is continuously smaller than the preset current in the period of the power-on self-test of the vehicle, i.e. step S303 is performed.

S303: counting a second duration time when the second coil current is smaller than the preset current, and judging whether the second duration time is larger than the second preset duration time or not; if the second duration is not greater than the second preset duration, step S304 is executed; if the second duration is longer than the second preset duration, step S305 is performed.

In the embodiment of the invention, the applicant researches find that after the vehicle is electrified, the vehicle is required to complete the power-on self-test of the vehicle in the shortest time as possible, so that based on the consideration of the four-wheel drive controller to detect the power-on self-test completion time of the vehicle, a corresponding second preset duration time can be preset, so that under the condition that the second coil current is determined to be smaller than the preset current, the second duration time of the transfer case coil can be counted, and whether the second duration time is larger than the second preset duration time or not can be judged; if the second duration is not longer than the second preset duration, it is indicated that the second coil current of the transfer case coil is gradually increased and gradually exceeds the preset current in the process of the vehicle power-on self-test, and at this time, the transfer case coil can be considered to meet the subsequent operation requirement, and it can be determined that the vehicle successfully completes the vehicle power-on self-test, that is, step S304 is executed.

If the second duration is longer than the second preset duration, which means that the second coil current of the transfer case coil is always smaller than the preset current in the process of power-on self-test of the vehicle, the transfer case coil may not meet the subsequent operation requirement at this time, and then step S305 may be executed.

It should be noted that, based on the consideration of the four-wheel drive controller detecting the power-on self-checking completion time of the vehicle, the second preset duration may be preset to 100ms, and the corresponding second preset duration may be set according to the actual application, which is not limited herein.

S304: and determining that the vehicle is powered on for self-checking.

S305: and determining that the transfer case coil has an open circuit fault, and generating and outputting corresponding open circuit fault information.

In the embodiment of the invention, in the process of vehicle power-on self-test, if the second coil current of the transfer case coil is always smaller than the preset current, then the transfer case coil can be considered to have an open-circuit fault currently, and further the open-circuit fault information of the corresponding transfer case coil can be generated, and the generated open-circuit fault information is output, so that a user is prompted that the transfer case coil has the open-circuit fault currently, and corresponding fault processing is performed timely.

In the specific execution of step S201, in the case where it is determined that the vehicle completes the power-on self-test, it may be determined that there is no open circuit fault in the transfer case coil when the vehicle is started, and the transfer case coil meets the subsequent operation requirement, so that the coil information of the transfer case coil may be obtained in the vehicle operation process.

S202: judging whether the transfer case coil meets preset running conditions according to coil information of the transfer case coil. If the transfer case coil meets the preset operation condition, step S203 is executed.

In the embodiment of the application, according to the application of the transfer case coil in the actual process, the coil resistance of the transfer case coil can be increased along with the increase of the temperature, so that the transfer case coil can work normally, the coil resistance of the transfer case coil is required to be ensured not to be excessively large, and the temperature of the transfer case coil is required to be ensured not to be excessively large too, otherwise, the follow-up whole vehicle operation can be influenced, therefore, the corresponding target temperature threshold and the maximum coil resistance can be preset, the corresponding relation between the target temperature threshold and the maximum coil resistance can be further set, and the corresponding preset operation condition can be set according to the preset target temperature threshold and the maximum coil resistance.

It should be noted that, the preset operation condition may indicate that the temperature of the transfer case coil is not greater than the target preset temperature value and/or the resistance of the transfer case coil is not greater than the maximum coil resistance, which may be set according to practical applications, and the embodiments of the present application are not limited herein.

For example, according to the temperature of the transfer case coil in actual operation, the coil resistance of the transfer case coil is actually measured, and the obtained coil resistance may be: at normal temperature (20 ℃), the coil resistance of the transfer case coil is r=2.5Ω; at 140 degrees celsius, the maximum coil resistance of the transfer case coil is 3Ω.

In the actual application process, the maximum temperature of the transfer case coil in the actual work is 140 ℃, and then the target temperature threshold value can be set to be 140 ℃; and the maximum value of the coil resistance of the transfer case coil within 140 ℃ is 3 omega, so that the maximum coil resistance can be set to be 3 omega, and the specific setting mode related to the target temperature threshold and the maximum coil resistance can be set according to practical application, and the embodiment of the invention is not limited.

In the process of specifically executing step S202, after the coil information of the corresponding transfer case coil is obtained, whether the temperature of the transfer case coil is greater than the target temperature threshold value and/or whether the resistance value of the transfer case coil is greater than the maximum coil resistance value may be further determined; if the temperature of the transfer case coil is not greater than the target temperature threshold value and/or the temperature of the transfer case coil is not greater than the maximum coil resistance value, the current temperature of the transfer case coil is normal, the condition that the whole vehicle operation is influenced due to overhigh temperature is avoided, the transfer case coil can be determined to meet the preset operation condition, and then the first duty ratio of the transfer case coil can be obtained; if the temperature of the transfer case coil is greater than the target temperature threshold value and/or the resistance of the transfer case coil is greater than the maximum coil resistance value, the current temperature of the transfer case coil can be considered to be too high, the running of the whole vehicle can be influenced, and it can be determined that the transfer case coil does not meet the preset running condition, and further corresponding whole vehicle fault information can be output to prompt a user to perform corresponding processing in time. Wherein the coil information includes a temperature of the transfer case coil and a resistance value of the transfer case coil.

S203: acquiring a first duty ratio of a transfer case coil, and judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio; if the transfer case coil satisfies the coil open diagnosis condition, step S204 is performed.

In the embodiment of the invention, the first preset duty cycle may be determined in advance according to the target temperature threshold and the preset output minimum voltage. The applicant finds that under the condition that the duty ratio of the transfer case coil is equal to 0, the four-wheel drive controller judges that the transfer case coil driving is not needed, and the transfer case coil open circuit does not influence the transfer case function; and under the condition that the duty ratio of the transfer case coil is larger than 0 and smaller than the first preset duty ratio, the open-circuit fault information of the corresponding transfer case coil is not output, namely the corresponding open-circuit fault operation is not acquired, and at the moment, if the front wheel and the rear wheel of the vehicle have a rotating speed difference, the four-wheel drive controller can continuously drive the transfer case coil according to the current duty ratio. Because the coil of the transfer case coil is open circuit and no current exists in the transfer case coil, friction plates in the transfer case cannot be pressed on demand, front and rear output torque cannot be intelligently distributed, but the front and rear wheels still have rotating speed difference, and at the moment, the four-wheel drive controller can continuously increase the duty ratio of coil driving; and when the duty ratio is greater than or equal to a first preset duty ratio, the four-wheel drive controller executes open circuit fault diagnosis of the transfer case coil.

In summary, the open-circuit fault diagnosis of the transfer case coil is not performed under the 0-first preset duty ratio, the transfer case function is not affected, and the faults of the transfer case coil are accurately judged when the coil is open-circuited, so that the situation that the system misreports the open-circuit faults of the transfer case coil to cause the vehicle to lose four driving forces can be effectively avoided, and the transfer case coil of the vehicle can be effectively detected by the four-wheel drive controller when the transfer case coil of the vehicle is indeed open-circuited, thereby ensuring the running reliability of the vehicle.

Optionally, the process of determining whether the transfer case coil meets the coil open circuit diagnosis condition according to the first duty cycle may specifically be: judging whether the first duty cycle is smaller than a first preset duty cycle or not; the first preset duty cycle is determined according to a target temperature threshold and a preset output minimum voltage; if the first duty cycle is smaller than the first preset duty cycle, determining that the transfer case coil does not meet the coil open circuit diagnosis condition; and if the first duty ratio is not smaller than the first preset duty ratio, determining that the transfer case coil meets the coil open circuit diagnosis condition.

It should be noted that, according to the requirement of the whole vehicle, the voltage range of the working voltage of the whole vehicle may be 9V-16V, that is, the minimum working voltage is 9V, and the maximum working voltage is 16, so that the preset output minimum voltage may be set to 9V, that is, the output voltage of the four-wheel drive controller may be set to 9V.

As an implementation manner of the embodiment of the present application, the process of determining the first preset duty ratio according to the target temperature threshold and the preset output minimum voltage may specifically be: determining the maximum coil resistance value matched with the target temperature threshold value; and determining a first preset duty cycle according to the preset output minimum voltage, the maximum coil resistance, the preset coil open threshold value and the preset coil open difference value.

Optionally, in some embodiments, the preset coil open threshold value and the preset coil open difference value may be added to obtain a corresponding sum value; multiplying the maximum coil resistance value by the sum value to obtain a corresponding product; the first preset duty cycle is calculated according to the product and the preset output minimum voltage.

In this embodiment, the current value of the transfer case coil loop may be monitored in real time by the four-wheel drive controller, and the monitored current value is set to a preset coil open threshold.

It should be noted that, through the research of the applicant, the current value of the transfer case coil loop monitored by the four-wheel drive controller is 0.1A, and further the preset coil open-circuit threshold value may be set to be 0.1A, and the preset coil open-circuit threshold value may be set according to practical application, which is not limited in this embodiment of the present invention.

In this embodiment, in order to ensure that the four-wheel drive controller can normally start the diagnostic function, that is, in order to ensure that the four-wheel drive controller can successfully perform open fault diagnosis on the distributor coil, it is necessary to ensure that the difference between the coil current of the distributor coil and the preset coil open threshold is maintained at a certain value, and then set a corresponding preset coil open difference.

In the actual application process, based on the actual vehicle test result, if the diagnosis function of the four-wheel drive controller is required to be normally started, the difference between the coil current of the transfer case coil and the preset coil open-circuit threshold is required to be maintained at 0.5A, that is, deltaT is more than or equal to 0.5A, that is, C-T is more than or equal to 0.5A; accordingly, the preset coil open difference value may be set to 0.5A. Wherein, deltaT is the difference value of the preset coil open circuit, C is the coil current limit of the transfer case coil, and T is the preset coil open circuit threshold.

The setting of the preset coil open-circuit difference value can be set according to practical application, and the embodiment of the invention is not limited herein.

In the embodiment of the invention, under the condition that the preset coil open-circuit threshold delta T is more than or equal to 0.5A, the duty ratio of the transfer case coil is calculated according to the preset output minimum voltage, the maximum coil resistance, the preset coil open-circuit threshold and the preset coil open-circuit difference, as shown in a formula (1).

D＝[(T+0.5)*Rmax*100％]/Umin (1)

Wherein D is a first preset duty ratio, T is a preset coil open-circuit threshold, rmax is a maximum coil resistance value, and Umin is a preset output minimum voltage.

For example, assuming that the preset coil open threshold T is 0.1A, the maximum coil resistance Rmax is 3Ω, the preset output minimum voltage Umin is 9V, and the preset output minimum voltage, the maximum coil resistance, the preset coil open threshold, and the preset coil open difference are brought into formula (1), D may be calculated to be equal to 20%, and further the first preset duty ratio may be set to 20%.

Referring to fig. 4, if the first preset duty cycle is 20%, the four-drive controller does not perform open fault diagnosis even if the transfer case coil is open when the first duty cycle of the transfer case coil is within 0-20%. The following can be specifically classified into two cases: (1) under the condition that the first duty ratio is equal to 0, the four-wheel drive controller judges that the transfer case coil driving is not needed, and at the moment, the transfer case coil open circuit does not influence the function of the transfer case; (2) when the first duty ratio is within 0-20%, the front wheel and the rear wheel of the vehicle have rotational speed differences because the duty ratio section does not carry out open circuit fault diagnosis, the four-wheel drive controller can continuously drive the transfer case coil according to the duty ratio of 0-20%, at the moment, because the transfer case coil is in an open circuit and does not have current, friction plates in the transfer case can not be pressed on demand, the front output torque and the rear output torque can not be distributed intelligently, but the front wheel and the rear wheel still have rotational speed differences, and at the moment, the four-wheel drive controller can continuously increase the duty ratio of the transfer case coil; when the first duty ratio is greater than or equal to 20%, the open circuit diagnosis function of the four-wheel drive control is started.

In summary, when the duty ratio of the transfer case coil is more than or equal to 20%, determining that the transfer case coil meets a coil open circuit diagnosis condition; and when the duty ratio of the transfer case is smaller than 20%, determining that the transfer case coil does not meet the coil open circuit diagnosis condition, namely, not performing open circuit fault diagnosis.

S204: when the first coil current of the transfer case coil is smaller than the preset current, counting a first duration time when the first coil current is smaller than the preset current, and judging whether the first duration time is larger than the first preset duration time or not; if the first duration is longer than the first preset duration, step S205 is performed.

In the embodiment of the invention, the applicant researches find that under the condition that the first duty ratio is smaller than the first preset duty ratio, the fault maturation time of the transfer case coil exists, that is, if the coil current of the transfer case coil is detected to be abnormal in the fault maturation time period, the open circuit fault of the transfer case coil can be determined; if there is no abnormality in the coil current of the transfer case coil, it may be determined that there is no open circuit fault in the transfer case coil. Accordingly, the corresponding first preset duration may be set based on the fault maturation time of the transfer coil.

In some embodiments, in order to ensure normal operation of the whole vehicle, after the vehicle has completed the power-on self-test, in order to further prevent the open-circuit fault of the transfer case coil from a fault, it is necessary to ensure that the duration that the coil current of the transfer case coil is less than the preset current cannot be too long and cannot be less than the time of the power-on self-test of the vehicle, so the first preset duration may be set to 500ms and may be set according to practical application, and embodiments of the present application are not limited herein.

In the process of specifically executing step S204, in the case where it is determined that the transfer case coil satisfies the coil open circuit diagnosis condition, the current coil current of the transfer case coil (for convenience of distinction, the coil current acquired at this time is referred to as a first coil current) may be collected again, and it is determined whether the first coil current is greater than a preset current; if the first coil current is not less than the preset current, returning to execute step S201; if the first coil current is smaller than the preset current, the first duration time that the first coil current limit of the transfer case coil is smaller than the preset current can be further counted, and whether the first duration time is larger than the first preset duration time or not is judged; if the first duration is not longer than the first preset duration, the engineering of the transfer case coil can be considered to be normal, and the step S201 is executed in a return mode; if the first duration is longer than the first preset duration, then it may be considered that the transfer case coil is open-circuited, i.e. step S205 is performed.

S205: an open circuit fault of the transfer case coil is determined.

In the process of specifically executing step S205, in the case where it is determined that an open-circuit fault occurs in the transfer case coil, corresponding open-circuit fault information of the transfer case coil may be further generated, and the open-circuit fault information may be output, so as to prompt a user that an open-circuit fault exists in the transfer case coil currently, and perform corresponding fault processing in time.

The invention provides a transfer case coil diagnosis method, which is applied to a four-wheel drive controller on a vehicle, wherein a timely transfer case is further arranged on the vehicle and comprises a transfer case coil, coil information of the transfer case coil is obtained under the condition that the vehicle finishes power-on self-test, and whether the transfer case coil meets preset running conditions is judged according to the coil information; when the transfer case coil meets a preset operation condition, acquiring a first duty ratio of the transfer case coil; judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio; if the transfer case coil meets the coil open circuit diagnosis condition, and the first coil current of the transfer case coil is smaller than the preset current, counting a first duration time when the first coil current is smaller than the preset current; and if the first duration is longer than the first preset duration, determining that the transfer case coil has an open circuit fault. According to the technical scheme provided by the invention, whether the transfer case coil meets the coil open circuit diagnosis condition can be judged according to the first duty ratio of the transfer case coil; if the coil open circuit diagnostic condition is met, determining whether an open circuit fault has occurred in the transfer case coil based further on the first coil current of the transfer case coil; if the coil open-circuit diagnosis condition is not met, whether the transfer case coil has an open-circuit fault is not required to be continuously judged, so that whether the transfer case coil has the open-circuit fault is judged according to the first coil current of the transfer case coil only when the coil open-circuit diagnosis condition is met, the situation that the system mistakenly reports the open-circuit fault of the transfer case coil to cause the vehicle to lose four driving forces can be effectively avoided, and the transfer case coil of the vehicle can be effectively detected by the four-wheel drive controller when the transfer case coil of the vehicle has the open-circuit fault indeed, so that the running reliability of the vehicle is ensured.

To further understand the foregoing, a specific application scenario is illustrated below.

As shown in fig. 5, assuming that the second preset duty cycle is set to 100%, the preset current is 0.1A, the second preset duration is 100ms, the first preset duty cycle is 20%, and the first preset duration is 500ms.

When the four-wheel drive controller detects that the vehicle is electrified, whether the second duty ratio of the time divider coil is equal to 100% or not can be detected; if it is detected that the second duty cycle is equal to 100% at power-up of the vehicle, it may be further detected whether the second duration of time when the second coil current of the transfer case coil is less than 0.1A is greater than 100ms; if the second duration of the second coil current is less than 0.1A for more than 100ms, it may be determined that the transfer case coil has an open circuit fault.

If the second duration of the second coil current is less than 0.1A and is not more than 100ms, the power-on self-test of the vehicle is determined to be completed, and then the temperature and the resistance of the transfer case coil can be obtained; if the temperature of the transfer case coil is not greater than the target temperature threshold value and the resistance of the transfer case coil is not greater than the maximum coil resistance, detecting whether the first duty cycle of the transfer case coil is less than 20%; if the first duty cycle is less than 20%, determining that the transfer case coil does not meet the coil open circuit diagnosis condition, and not performing corresponding coil open circuit diagnosis; if the first duty cycle is not less than 20%, it may be determined that the transfer case coil meets the coil open circuit diagnostic condition, and it may be continued to detect if the first duration of the transfer case coil with the first coil current less than 0.1A is greater than 500ms; if the first coil current of the transfer case coil is longer than 500ms and is smaller than the first duration of 0.1A, determining that an open-circuit fault occurs in the transfer case coil, and determining the open-circuit fault position of the transfer case coil; if the first coil current of the transfer case coil is less than the first duration of 0.1A and not greater than 500ms, it may be determined that the transfer case coil is functioning properly.

Based on the above-mentioned diagnostic method for a transfer case coil provided by the embodiment of the present invention, the embodiment of the present invention further provides a diagnostic system for a transfer case coil, as shown in fig. 6, which includes:

a first judging unit 61, configured to acquire coil information of the transfer case coil, and judge whether the transfer case coil meets a preset operation condition according to the coil information;

a first acquisition unit 62 for acquiring a first duty cycle of the transfer case coil if the transfer case coil meets a preset operating condition;

a second judging unit 63 for judging whether the transfer case coil satisfies the coil open circuit diagnosis condition according to the first duty ratio;

a first statistics unit 64 for counting a first duration of time that the first coil current is less than the preset current if the transfer case coil meets the coil open circuit diagnostic condition and the first coil current of the transfer case coil is less than the preset current;

the first determining unit 65 is configured to determine that the open circuit fault occurs in the transfer case coil if the first duration is longer than the first preset duration.

The specific principle and execution process of each unit in the transfer case coil diagnostic system disclosed in the above embodiment of the present invention are the same as those of the transfer case coil diagnostic method disclosed in fig. 2 of the above embodiment of the present invention, and reference may be made to corresponding parts in the transfer case coil diagnostic method disclosed in the above embodiment of the present invention, and no further description is given here.

The invention provides a transfer case coil diagnosis system, which is used for acquiring coil information of a transfer case coil and judging whether the transfer case coil meets preset running conditions according to the coil information; when the transfer case coil meets a preset operation condition, acquiring a first duty ratio of the transfer case coil; judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio; if the transfer case coil meets the coil open circuit diagnosis condition, and the first coil current of the transfer case coil is smaller than the preset current, counting a first duration time when the first coil current is smaller than the preset current; and if the first duration is longer than the first preset duration, determining that the transfer case coil has an open circuit fault. According to the technical scheme provided by the invention, whether the transfer case coil meets the coil open circuit diagnosis condition can be judged according to the first duty ratio of the transfer case coil; if the coil open circuit diagnostic condition is met, determining whether an open circuit fault has occurred in the transfer case coil based further on the first coil current of the transfer case coil; if the coil open-circuit diagnosis condition is not met, whether the transfer case coil has an open-circuit fault is not required to be continuously judged, so that whether the transfer case coil has the open-circuit fault is judged according to the first coil current of the transfer case coil only when the coil open-circuit diagnosis condition is met, the situation that the system mistakenly reports the open-circuit fault of the transfer case coil to cause the vehicle to lose four driving forces can be effectively avoided, and the transfer case coil of the vehicle can be effectively detected by the four-wheel drive controller when the transfer case coil of the vehicle has the open-circuit fault indeed, so that the running reliability of the vehicle is ensured.

Optionally, the transfer case coil diagnostic system provided by the present invention further includes:

the detection unit is used for detecting whether the second duty ratio of the transfer case coil is a second preset duty ratio or not when the power-on of the vehicle is detected;

the acquisition unit is used for acquiring second coil current of the transfer case coil if the second duty ratio is a second preset duty ratio;

the second statistics unit is used for counting a second duration time when the second coil current is smaller than the preset current and judging whether the second duration time is larger than the second preset duration time or not if the second coil current is smaller than the preset current;

and the second determining unit is used for determining that the vehicle finishes the power-on self-test and executing the first acquiring unit if the second duration is not greater than the second preset duration.

Optionally, the transfer case coil diagnostic system provided by the present invention further includes:

and the third determining unit is used for determining that the open circuit fault exists in the transfer case coil if the second duration is longer than the second preset duration.

Optionally, the first judging unit includes:

a second acquisition unit configured to acquire coil information of the transfer case coil; wherein the coil information includes a temperature of the transfer case coil and/or a transfer case coil resistance;

The third judging unit is used for judging whether the temperature of the transfer case coil is greater than a target temperature threshold value and/or whether the resistance of the transfer case coil is greater than a maximum coil resistance value;

a fourth determining unit, configured to determine that the transfer case coil meets a preset operation condition if the temperature of the transfer case coil is not greater than a target temperature threshold value and/or the resistance of the transfer case coil is not greater than a maximum coil resistance value;

and the fifth determining unit is used for determining that the transfer case coil does not meet the preset running condition if the temperature of the transfer case coil is greater than the target temperature threshold value and/or the resistance value of the transfer case coil is greater than the maximum coil resistance value.

Optionally, the second judging unit includes:

a third judging unit for judging whether the first duty cycle is smaller than a first preset duty cycle; wherein the first preset duty cycle is determined by the sixth determining unit according to the target temperature threshold and the preset output minimum voltage;

a seventh determining unit, configured to determine that the transfer case coil does not satisfy the coil open circuit diagnostic condition if the first duty cycle is smaller than a first preset duty cycle;

the eighth actuator coil satisfies the coil open circuit diagnostic condition.

Optionally, the sixth determining unit includes:

a ninth determining unit, configured to determine a maximum coil resistance value that matches the target temperature threshold;

The first calculation unit is used for determining a first preset duty ratio according to a preset output minimum voltage, a maximum coil resistance, a preset coil open-circuit threshold value and a preset coil open-circuit difference value.

Optionally, the first computing unit includes:

the second calculation unit is used for adding the preset coil open-circuit threshold value and the preset coil open-circuit difference value to obtain a corresponding sum value;

the third calculation unit is used for multiplying the maximum coil resistance value by the sum value to obtain a corresponding product;

and a fourth calculation unit for calculating a first preset duty cycle according to the product and a preset output minimum voltage.

Optionally, the transfer case coil diagnostic system provided by the present invention further includes:

and the output unit is used for generating corresponding open-circuit fault information of the transfer case coil and outputting the open-circuit fault information.

The embodiment of the invention provides a vehicle, which comprises the four-wheel drive controller provided by the embodiment of the application, and the four-wheel drive controller is used for executing any of the transfer case coil diagnosis manufacturing methods disclosed by the embodiment of the application.

In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for a system or system embodiment, since it is substantially similar to a method embodiment, the description is relatively simple, with reference to the description of the method embodiment being made in part. The systems and system embodiments described above are merely illustrative, wherein elements illustrated as separate elements may or may not be physically separate, and elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative elements and steps are described above generally in terms of functionality in order to clearly illustrate the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims (10)

1. A method of transfer case coil diagnostics, the method comprising:

acquiring coil information of a transfer case coil, and judging whether the transfer case coil meets preset running conditions according to the coil information;

if the transfer case coil meets the preset running condition, acquiring a first duty ratio of the transfer case coil;

judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio;

if the transfer case coil meets the coil open circuit diagnosis condition, and the first coil current of the transfer case coil is smaller than a preset current, counting a first duration time that the first coil current is smaller than the preset current;

and if the first duration is longer than the first preset duration, determining that the transfer case coil has an open circuit fault.

2. The method according to claim 1, wherein the method further comprises:

Detecting whether the second duty cycle of the transfer case coil is a second preset duty cycle when the power-on of the vehicle is detected;

if the second duty cycle is the second preset duty cycle, collecting second coil current of the transfer case coil;

if the second coil current is smaller than the preset current, counting a second duration time when the second coil current is smaller than the preset current, and judging whether the second duration time is larger than a second preset duration time or not;

and if the second duration is not greater than the second preset duration, determining that the vehicle is complete to power on self-test, and executing the step of acquiring coil information of the transfer case coil.

3. The method according to claim 2, wherein the method further comprises:

and if the second duration is longer than the second preset duration, determining that the transfer case coil has an open circuit fault.

4. The method of claim 1, wherein the obtaining coil information of the transfer case coil and determining whether the transfer case coil meets a preset operating condition based on the coil information comprises:

acquiring coil information of a transfer case coil; wherein the coil information includes a temperature of the transfer case coil and/or a transfer case coil resistance;

Judging whether the temperature of the transfer case coil is greater than a target temperature threshold value and/or whether the resistance of the transfer case coil is greater than a maximum coil resistance value;

if the temperature of the transfer case coil is not greater than the target temperature threshold value and/or the resistance of the transfer case coil is not greater than the maximum coil resistance, determining that the transfer case coil meets the preset running condition;

and if the temperature of the transfer case coil is greater than the target temperature threshold value and/or the resistance value of the transfer case coil is greater than the maximum coil resistance value, determining that the transfer case coil does not meet the preset running condition.

5. The method of claim 1, wherein said determining whether the transfer case coil meets a coil open circuit diagnostic condition based on the first duty cycle comprises:

judging whether the first duty cycle is smaller than a first preset duty cycle or not; wherein the first preset duty cycle is determined according to the target temperature threshold and a preset output minimum voltage;

if the first duty cycle is smaller than the first preset duty cycle, determining that the transfer case coil does not meet a coil open circuit diagnosis condition;

and if the first duty ratio is not smaller than the first preset duty ratio, determining that the transfer case coil meets the coil open circuit diagnosis condition.

6. The method of claim 5, wherein said determining said first preset duty cycle based on said target temperature threshold and a preset output minimum voltage comprises:

determining the maximum coil resistance value matched with the target temperature threshold value;

and determining the first preset duty ratio according to a preset output minimum voltage, the maximum coil resistance, a preset coil open-circuit threshold value and a preset coil open-circuit difference value.

7. The method of claim 6, wherein determining the first preset duty cycle based on a preset output minimum voltage, the maximum coil resistance, a preset coil open threshold, and a preset coil open difference value comprises:

adding a preset coil open-circuit threshold value and the preset coil open-circuit difference value to obtain a corresponding sum value;

multiplying the maximum coil resistance by the sum to obtain a corresponding product;

and calculating the first preset duty cycle according to the product and the preset output minimum voltage.

8. The method of claim 1 or 3, wherein after determining that the transfer case coil has failed open, the method further comprises:

and generating corresponding open-circuit fault information of the transfer case coil, and outputting the open-circuit fault information.

9. A transfer case coil diagnostic system, the system comprising:

the first judging unit is used for acquiring coil information of the transfer case coil and judging whether the transfer case coil meets preset running conditions or not according to the coil information;

a first acquisition unit for acquiring a first duty cycle of the transfer case coil if the transfer case coil meets the preset operating condition;

the second judging unit is used for judging whether the transfer case coil meets a coil open circuit diagnosis condition according to the first duty ratio;

the first statistical unit is used for counting a first duration time when the first coil current of the transfer case coil is smaller than the preset current if the transfer case coil meets the coil open circuit diagnosis condition;

and the first determining unit is used for determining that the transfer case coil has an open circuit fault if the first duration is longer than the first preset duration.

10. A vehicle comprising a four-wheel drive controller for performing the transfer case coil diagnostic method of any of claims 1-8.