Dry-running protection method for electronic water pump
Technical Field
The invention relates to the technical field of electronic water pumps of engines, in particular to a dry-running protection method for an electronic water pump.
Background
Along with the development of the technology, an electrical control element replaces a traditional mechanical control element, an electronic water pump comprises a motor, a controller, a bearing, a sealing element and the like, the working and running processes of the electronic water pump are summarized, and all the components need cooling liquid to be cooled so as to achieve an ideal working state; once the coolant is lost, the components are damaged by high temperature, such as motor ablation, controller ablation, seal ablation, etc. Therefore, electronic products are generally provided with a dry-running protection method, and the change of the load at the impeller end is identified through the running current of the motor to judge whether the cooling liquid is lost.
In the conventional electronic water pump dry-running protection method, through system calibration, the current consumed by the water pump at a specific rotating speed is set as a threshold value, namely when the electronic water pump runs to the rotating speed, if the current value is lower than the threshold value, the load of the impeller end of the electronic water pump is considered to be low at the moment, the electronic water pump is in a water shortage state, the electronic water pump is immediately shut down, and meanwhile, a fault code is sent to an ECU of the whole vehicle. The control mode has misjudgment, because the electronic water pump has the same power output state, P is UI, the current is inversely proportional to the voltage, namely the larger the voltage is, the smaller the current is, but the output power of the water pump is the same at the moment, namely the rotating speed is constant; when the voltage of the whole vehicle system changes instantaneously, the current also has an instantaneous low peak value, the phenomenon generally exists in a new energy hybrid vehicle type at the present stage, and the electronic water pump is stopped at the moment, which is misjudged. In addition, when the cooling liquid is added again in the after-sale maintenance of the vehicle, gas is inevitably existed in the system, the exhaust operation is generally carried out, and in the exhaust process, when the gas passes through the impeller of the electronic water pump, the misjudgment is also existed, and a false alarm is sent out.
Disclosure of Invention
This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.
The invention is provided in view of the above and/or the problems existing in the existing electronic water pump dry-running protection method.
Therefore, the problem to be solved by the invention is how to prevent the electronic water pump from performing water shortage dry rotation.
In order to solve the technical problems, the invention provides the following technical scheme: a dry-running protection method for electronic water pump includes such steps as providingSetting a current value filtering range t, and setting a current protection threshold IDryRun(ii) a Raising the speed of the electronic water pump to a test rotating speed NTestDryRunTime period T0The current of the internal electronic water pump is lower than a protection threshold IDryRunWhen the electronic water pump is started, the electronic water pump automatically reduces the speed to a specific rotating speed N1In the operating period T1Then, the electronic water pump is accelerated to the testing rotating speed NTestDryRunDetect T again0The current of the internal electronic water pump is circulated for n times according to the steps. Judging T in n detection processes0Whether the current of the internal electronic water pump is lower than a protection threshold IDryRun: when T is detected0The current of the internal electronic water pump is higher than a protection threshold I for the first timeDryRunWhen the electronic water pump works normally, the electronic water pump stops detecting according to the signal; when T is detected0The current of the internal electronic water pump is always lower than a protection threshold IDryRunWhen the electronic water pump is stopped, the fault code is reported, and at interval time T2Then, the electronic water pump is set and restarted, and is accelerated to the testing rotating speed NTestDryRunAnd carrying out dry rotation detection again, and if the dry rotation fault is still judged, reducing the speed of the electronic water pump to a specific rotating speed N1Sustained operation period T3Then the machine is stopped and is not restarted.
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: the current value is filtered to be the current value of the short-time peak value.
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: the current protection threshold IDryRunThe phase current in the electronic water pump.
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: the electronic water pump dry rotation detection is carried out when the electronic water pump is started for the first time after power-on reset.
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: the specific rotating speed N1Less than the test speed NTestDryRun。
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: in the interval period T2Then, againSecondary detection, when T is detected0The current of the internal electronic water pump is higher than a protection threshold I for the first timeDryRunAnd eliminating the fault code, normally operating the electronic water pump according to the signal, and stopping detection.
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: and the fault code is sent to the automobile instrument desk.
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: the current of the electronic water pump is always higher than a protection threshold I within at least 200msDryRunThe electronic water pump can normally operate according to the signal and stop detecting.
As a preferable scheme of the electronic water pump dry-running protection method of the invention, the method comprises the following steps: the number of cycles n is at least greater than 2.
The method has the advantages that when the electronic water pump identifies the dry running for the first time, through the execution of the method, a plurality of confirmation processes such as speed reduction, speed rise re-detection and the like are carried out on the electronic water pump, whether the electronic water pump runs dry due to water shortage is finally judged, so that the generation of misjudgment is avoided, the electronic water pump is protected, and meanwhile, the functional influence on a cooling system caused by misjudgment shutdown of the electronic water pump is avoided.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:
fig. 1 is a diagram illustrating a variation of an actual operating speed of an electronic water pump in the dry-run protection method of the electronic water pump.
Fig. 2 is a logic diagram of the dry-running protection method of the electronic water pump according to the present invention.
Fig. 3 is a logic diagram of a dry run protection method of an electronic water pump in the prior art.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
Example 1
The first embodiment of the invention provides a dry-running protection method for an electronic water pump, which can solve the following problems:
because the electronic water pump is in the same power output state, the current is inversely proportional to the voltage, namely the larger the voltage is, the smaller the current is, but the output power of the water pump is the same at the moment, namely the rotating speed is constant; when the voltage of the whole vehicle system changes instantaneously, the current also has an instantaneous low peak value, the phenomenon generally exists in a new energy hybrid vehicle type at the present stage, and the electronic water pump is stopped at the moment, which is misjudged. In addition, when the cooling liquid is added again in the after-sale maintenance of the vehicle, gas is inevitably existed in the system, the exhaust operation is generally carried out, and in the exhaust process, when the gas passes through the impeller of the electronic water pump, the misjudgment is also existed, and a false alarm is sent out.
In addition, as shown in fig. 3, in the conventional electronic water pump dry-running protection method, through system calibration, the current consumed at a fixed rotation speed of the water pump is set to be a threshold value, that is, when the electronic water pump runs to the rotation speed, if the current value is lower than the threshold value, the load at the impeller end of the electronic water pump is considered to be low at the moment, the electronic water pump is in a water shortage state, then the electronic water pump is shut down, and meanwhile, a fault code is sent to the ECU of the. Such a control method may cause erroneous determination.
Therefore, the electronic water pump dry-running protection method can be used for not only realizing the engine electronic water pump dry-running protection method, but also performing a plurality of confirmation processes such as speed reduction, speed rise re-detection and the like on the electronic water pump through the execution of the method, and finally judging whether the electronic water pump is lack of water and dry-running, so that the generation of misjudgment is avoided, the electronic water pump is protected, and the functional influence on a cooling system caused by misjudgment and shutdown of the electronic water pump is avoided.
The dry-running protection method of the electronic water pump comprises the following steps: s1: setting a current value filtering range t and setting a current protection threshold IDryRun(ii) a S2: starting the electronic water pump; s3: detecting for the first time; s4: and (5) carrying out second cycle detection.
Specifically, the following specific embodiments may be adopted:
first, the step S1 includes:
s11: setting a current value filtering range t and setting a current protection threshold IDryRunThe current value filtering is the current value of the short-time peak value, and the short-time peak value is not used as a judgment basis, so that the short-time peak value needs to be removed, and the electronic water pump can be prevented from being stopped and misjudged due to the fact that the voltage of the whole vehicle system changes instantly. Current protection threshold iDryRunThe lowest current value.
Step S2 includes:
s21: and starting the electronic water pump.
Step S3 in the above step includes:
s31: increasing the speed to the testing rotating speed NTestDryRun(ii) a Wherein the rotation speed N is measuredTestDryRunIs a fixed rotational speed.
S32: judging the time period T0Whether the current of the internal electronic water pump is lower than a protection threshold IDryRun(ii) a If time period T0The current of the internal electronic water pump is lower than a protection threshold IDryRunThen proceed to step S23, if time period T is reached0The current of the internal electronic water pump is higher than a protective threshold IDryRunAnd if so, the electronic water pump normally operates according to the signal and stops detection.
S33: automatic speed reduction of electronic water pump to specific rotating speed N1Run T1The period of time.
S34: circularly performing the steps S21 to S23 for n times; if after n cycles, the time period T0The current of the internal electronic water pump is always lower than a protection threshold IDryRunAnd the electronic water pump is stopped, and a fault code is reported to the instrument desk.
Step S4 in the above step includes:
s41: in the interval period T2Then, performing the step 2 to the step 3 again; if step S32 is being performed, the time period T0The current of the internal electronic water pump is higher than a protective threshold IDryRunAnd if so, the electronic water pump normally operates according to the signal, stops detection and eliminates the fault code. If n cycles are performed, the time period T0The current of the internal electronic water pump is always lower than a protection threshold IDryRunThe electronic water pump is decelerated to a specific rotating speed N1Sustained operation period T3Then the machine is stopped and is not restarted.
Fig. 2 is a variation of the operating speed of the actual electronic water pump in the process. First, the speed is increased from 0 to NTestDryRunDetecting T0Time, if the current is below the protection threshold IDryRunThen decrease the speed to N1Run T1After a time (e.g. 3 seconds), the speed is increased to NTestDryRunJudging whether the current is lower than a protection threshold IDryRunIf the current is lower than the protection threshold I, the dry-running detection process is ended, if the current is still lower than the threshold, the detection is continued, and after n times (for example, 3 times) of continuous detection, if the current is still lower than the protection threshold IDryRunThen decrease the speed to N1Operation T3Time (e.g. 10 minutes), final speed drop to 0 and shut down, with the double slash in figure 2 meaning multiple cycles are provided.
By adopting the steps, the electronic water pump is subjected to a plurality of confirmation processes such as speed reduction, speed increase, redetection and the like through the execution of the method, and whether the electronic water pump is lack of water and is dry to rotate is finally judged, so that the generation of misjudgment is avoided, the electronic water pump is protected, and the functional influence of misjudgment and shutdown of the electronic water pump on a cooling system is avoided.
It is to be noted that the specific rotation speed N1Less than the test speed NTestDryRun. At a specific speed N1The operation is to prevent the electronic water pump from stopping due to misjudgment in the detection process and the functional influence on the cooling system, and when the step S41 is carried out, the electronic water pump is decelerated to the specific rotating speed N1Sustained operation period T3And stopping the machine, and also preventing misjudgment from influencing the cooling system.
It is noted that the electric pump current is always above the protection threshold i for at least 200msDryRunThe electronic water pump can normally operate and stop detecting according to the signal because the current of the electronic water pump is higher than the protection threshold I in 200msDryRunPossibly a short-time peak value caused by instantaneous voltage change of the whole vehicle system;
as can be seen from the comparison between fig. 1 and fig. 3 and the above description, compared with the prior art, the method of the present invention increases the current value filtering range t, the multiple loop detection, and the multiple speed reduction to N1The steps are operated for a certain time, and by adding the steps, the method of the invention prevents the damage of the dry turning to the parts and also prevents the occurrence of misjudgment.
Example 2
The second embodiment of the present invention provides a dry-running protection method for an electronic water pump, which is different from the first embodiment in that: the number of cycles n is at least greater than 2. In the previous embodiment, the dry-running protection method for the electronic water pump comprises the following steps:
s1: setting a current value filtering range t and setting a current protection threshold IDryRun(ii) a S2: starting the electronic water pump; s3: detecting for the first time; s4: and (5) carrying out second cycle detection.
Specifically, the following specific embodiments may be adopted:
first, the step S1 includes:
s11: the current value filtering range t <200ms is set, and the current protection threshold value 7A is set.
Step S2 includes:
s21: and starting the electronic water pump.
Step S3 in the above step includes:
s31: the speed is increased to the testing rotating speed of 4500 r/min.
S32: and judging whether the current of the electronic water pump is lower than a protection threshold 7A in the time period 2 s. If the current of the electronic water pump is lower than the protection threshold 7A within the time period 2S, performing S23; and if the current of the electronic water pump is higher than the protection threshold value 7A within the time period of 2s, the electronic water pump normally operates according to the signal, and the detection is stopped.
S33: the electronic water pump automatically reduces the speed to a specific rotating speed of 3000r/min, and the running time period is 3 s.
S34: circularly performing the steps S21 to S23 for 3 times; if after 3 times of circulation, under the condition that the revolution number is 4500r/min, the current of the electronic water pump is always lower than a protection threshold value 7A, the electronic water pump is stopped, and a fault code is reported to an instrument desk.
Step S4 in the above step includes:
s41: after the interval time is 5s, performing the step 2 to the step 3 again; if the rotation number is 4500r/min and the current of the electronic water pump is higher than the protection threshold 7A when step S32 is performed, the electronic water pump normally operates according to the signal, the detection is stopped, and the fault code is eliminated. If the circulation is carried out for 3 times again, under the condition that the revolution is 4500r/min, the current of the electronic water pump is always lower than a protection threshold value 7A, the electronic water pump is stopped after being decelerated to a specific rotating speed of 3000r/min for continuous operation time of 10min, and the electronic water pump is not restarted.
In step S11, the current value filtering range t <200ms means that if the current value is lower than the protection threshold (7A) and lasts shorter than 200ms, the current variation will be filtered.
By executing the method, a plurality of confirmation processes such as speed reduction, speed increase, redetection and the like are carried out on the electronic water pump, and whether the electronic water pump is lack of water and dry-running is finally judged, so that misjudgment is avoided, the electronic water pump is protected, and functional influence on a cooling system caused by misjudgment shutdown of the electronic water pump is avoided.
If the prior art shown in fig. 3 is adopted, the anti-dry rotation protection method comprises the following steps:
s1: and starting the electronic water pump.
S2: the speed is increased to the testing rotating speed of 4500 r/min.
S3: and judging whether the current of the electronic water pump is lower than a protection threshold 7A in the time period 2 s. If the current of the electronic water pump is lower than the protection threshold value 7A within the time period of 2s, stopping the electronic water pump; and if the current of the electronic water pump is higher than the protection threshold value 7A within the time period of 2s, the electronic water pump normally operates according to the signal, and the detection is stopped.
Compared with the method, the method has the advantages that the filtering range t of the current value is less than 200ms, multiple times of circulating detection and multiple times of speed reduction to 3000r/min are set for a certain time, and through the addition of the steps, the method removes the influence of instantaneous current (the current within 200 ms) on dry-running detection; the possibility of misjudgment is reduced by multiple times of cyclic detection; the electronic water pump is prevented from being stopped due to misjudgment in the detection process when the speed is reduced to 3000r/min for a certain time, and the functional influence on a cooling system is prevented.
The number of cycles n is preferably 3, since the number of cycles n is at least greater than 2, and the greater the number of cycles, the lower the possibility of erroneous determination, but the greater the number of cycles, the lower the performance of the electronic water pump.
It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.