A Diagnostic Method for a Stopwatch

Abstract

An embodiment of the present application provides a diagnostic method for a shutdown timer, including: obtaining an array EOT<subgt;[n]< / subgt> including the engine shutdown times of a continuous preset number n; obtaining the range Δt in the array EOT<subgt;[n]< / subgt>; if the range Δt meets the set condition, it is determined that there is an unreasonable fault in the shutdown timer. That is to say, according to whether the range Δt meets the set condition, it is determined whether there is a fault in the shutdown timer. In this way, even if the chip has an abnormality and cannot effectively identify the fault of the shutdown timer, it can still be determined whether there is an unreasonable fault in the shutdown timer according to whether the range Δt meets the set condition, solving the problem in the prior art that the diagnostic logic of the shutdown timer depends on the self-diagnosis result of the chip itself, improving the diagnostic accuracy, increasing the diagnostic redundancy, and at the same time, the diagnostic logic strategy is simple and the development cost is low.

Description

Technical Field

[0001] This application relates to the technical field of shutdown timers, and particularly to a diagnostic method for a shutdown timer. Background Art

[0002] As one of the basic components of the Engine Management System (EMS), the shutdown timer is often integrated inside the engine control unit, mainly providing the Engine off Time (EOT) signal for the engine management system. The EOT signal is widely used in the control strategies (such as start control) and diagnostic strategies (such as the rationality diagnosis of the coolant temperature sensor in the cooling system) of the engine management system. Therefore, it is very necessary to perform corresponding diagnostic monitoring on the shutdown timer.

[0003] In the related art, the common method is to use the self - diagnosis function of the shutdown timer chip to identify invalid states and convey the invalid information to the basic software layer. The engine management system reports the unreasonable fault of the shutdown timer through the application software layer. This diagnostic method depends on the self - diagnosis result of the shutdown timer chip itself. If the chip malfunctions, there may be a problem that the fault cannot be effectively identified. Summary of the Invention

[0004] In view of this, embodiments of this application are expected to provide a diagnostic method for a shutdown timer to solve the problem that the fault cannot be effectively identified after the chip malfunctions in the related art.

[0005] To achieve the above object, embodiments of this application provide a diagnostic method for a shutdown timer, and the diagnostic method includes:

[0006] Obtain an array EOT including the engine shutdown times for a continuous preset number n [n] ;

[0007] Obtain the range Δt in the array EOT [n] ;

[0008] If the range Δt meets the set condition, it is determined that the shutdown timer has a fault.

[0009] In one implementation, the set condition is that the range Δt is less than or equal to a set threshold t.

[0010] In one implementation, the set threshold t is [0, 3] seconds.

[0011] In one implementation, the preset number n is [3, 5] times.

[0012] In one implementation, the step of obtaining an array EOT including the engine shutdown times for a continuous preset number n[n] steps, including multiple steps of obtaining the EOT.

[0013] In one embodiment, the step of obtaining the EOT specifically includes:

[0014] When the engine switches to the shutdown state, the shutdown timer starts timing;

[0015] Detect whether the diagnostic enable condition is satisfied;

[0016] If the diagnostic enable condition is satisfied, the shutdown timer stops timing and obtains the EOT.

[0017] In one embodiment, after the step that if the diagnostic enable condition is satisfied, the shutdown timer stops timing and obtains the EOT, it further includes:

[0018] The EOT of the shutdown timer is cleared.

[0019] In one embodiment, the diagnostic enable condition includes: the engine satisfies a first preset condition, and the shutdown timer satisfies a second preset condition.

[0020] In one embodiment, the first preset condition is that the engine switches to the running state.

[0021] In one embodiment, the second preset condition is that the signal of the shutdown timer is valid.

[0022] The embodiment of the present application provides a diagnostic method for a shutdown timer, including: obtaining an array EOT including the engine shutdown time of consecutive preset times n [n] ; obtaining the array EOT [n] The range Δt in; if the range Δt satisfies the set condition, it is determined that there is an unreasonable fault in the shutdown timer. That is to say, by obtaining the engine shutdown time during the consecutive n start-stop cycles of the engine and obtaining the range Δt in the array EOT [n] That is, calculating the absolute difference between the maximum value EOT max of the engine shutdown time and the minimum value EOT min of the engine shutdown time is the range Δt. When the range Δt satisfies the set condition, it can be determined that there is an unreasonable fault in the shutdown timer. In this way, even if the chip has an abnormality and cannot effectively identify the fault of the shutdown timer, it can still be determined whether there is an unreasonable fault in the shutdown timer according to whether the range Δt satisfies the set condition, solving the problem that the diagnostic logic of the shutdown timer in the prior art depends on the self-diagnosis result of the chip itself, improving the diagnostic accuracy, increasing the diagnostic redundancy, and at the same time, the diagnostic logic strategy is simple and the development cost is low. Description of the Drawings

[0023] Figure 1 Schematic diagram of a method for diagnosing a stopwatch provided by an embodiment of the present application;

[0024] Figure 2 Flow chart of a method for diagnosing a stopwatch provided by an embodiment of the present application. Detailed implementation manners

[0025] It should be noted that, without conflict, the embodiments in the present application and the technical features in the embodiments may be combined with each other. The detailed description in the detailed implementation manners should be understood as an explanatory illustration of the gist of the present application and should not be regarded as an improper limitation to the present application.

[0026] An embodiment of the present application provides a method for diagnosing a stopwatch. Please refer to Figure 1 , which is used for a stopwatch. The diagnostic method includes:

[0027] Step S101: Obtain an array EOT including the engine shutdown times of a continuous preset number n [n] ;

[0028] Step S102: Obtain the range Δt in the array EOT [n] ;

[0029] Step S103: If the range Δt meets the set condition, it is determined that there is an unreasonable fault in the stopwatch.

[0030] Among them, the engine can be a diesel engine, a gasoline engine, an electric vehicle motor, a hybrid engine, etc. It can be understood that during the engine start-stop cycle, there is a certain range of deviation between the multiple consecutive engine shutdown times of the engine. When the difference between the maximum value and the minimum value of the engine shutdown times within a certain number of times does not show a certain range of deviation, that is, if the range Δt does not meet the set condition, it can be determined that the engine shutdown times within this certain number of times are incorrect. And the engine shutdown time is recorded by the stopwatch. Therefore, it can be determined whether there is an unreasonable fault in the stopwatch according to whether the range Δt meets the set condition.

[0031] By obtaining the engine shutdown times of a continuous preset number n to form an array EOT [n] , the absolute difference between the maximum value EOT of the engine shutdown times in the array EOT [n] and the minimum value EOT of the engine shutdown times is the range Δt. max and the maximum value EOT of the engine shutdown times min is the range Δt.

[0032] The diagnostic method for the engine shutdown timer provided by the embodiments of the present application includes: obtaining an array EOT[n] including the engine shutdown times for a continuous preset number n; obtaining the range Δt in the array EOT[n]; if the range Δt meets the set conditions, it is determined that there is an unreasonable fault in the shutdown timer. That is to say, by obtaining the engine shutdown times during the continuous n start-stop cycles of the engine and obtaining the range Δt in the array EOT[n], that is, calculating the maximum value EOT of the engine shutdown time max and the minimum value EOT of the engine shutdown time min and the absolute difference is the range Δt. When the range Δt meets the set conditions, it can be determined that there is an unreasonable fault in the shutdown timer. In this way, even if the chip has an abnormality and cannot effectively identify the fault of the shutdown timer, it can still be determined whether there is an unreasonable fault in the shutdown timer according to whether the range Δt meets the set conditions, solving the problem in the prior art that the diagnostic logic of the shutdown timer depends on the self-diagnosis result of the chip itself, improving the diagnostic accuracy, increasing the diagnostic redundancy. At the same time, the diagnostic logic strategy is simple and the development cost is low.

[0033] The set deviation value within a certain range is the set threshold t. Compare the obtained range Δt with the set threshold t. According to the comparison result, it can be obtained whether there is a deviation of the set threshold t in the engine shutdown times for the continuous preset number n, so as to determine whether there is an unreasonable fault in the shutdown timer. The diagnostic method for the shutdown timer provided by this embodiment utilizes the characteristic that there is a deviation within a certain range in the engine shutdown times during the continuous certain number of start-stop cycles of the engine. By limiting the certain number to the preset number n and reasonably setting the deviation within a certain range as the set threshold t, and then performing the fault diagnosis of the shutdown timer, it solves the problem that the diagnostic logic of the existing shutdown timer depends on the self-diagnosis result of the chip itself, and at the same time improves the diagnostic accuracy and increases the diagnostic redundancy.

[0034] Step S101: Obtain an array EOT including the engine shutdown times for a continuous preset number n [n] ;

[0035] The engine shutdown time of the engine is the time difference between the time point when the engine starts and the time point when the engine stopped running last time. After the engine stops running, the shutdown timer starts to accumulate time from 0 seconds until the engine starts running next time. The shutdown timer feeds back the time accumulation value recorded at this moment as the engine shutdown time of this engine to the engine control unit. For each start-stop cycle of the engine, the shutdown timer feeds back the corresponding recorded time accumulation value to the engine control unit.

[0036] Among them, the engine control unit exists as the control core, records and stores the engine shutdown time fed back by the shutdown timer, and executes the diagnostic logic according to the accumulated engine shutdown time to determine whether there is an unreasonable fault in the shutdown timer.

[0037] It can be understood that after the engine undergoes multiple start-stop cycles, the engine control unit has obtained the corresponding number of engine shutdown times. According to the value of the preset number n, the preset number n can be determined according to actual diagnostic requirements, and this application does not limit it here. Obtain the engine shutdown times of consecutive preset number n to form an array EOT. [n] That is to say, after the engine starts and runs this time, the time cumulative value of the shutdown timer from the time point when the engine stopped running last time to the time point when it starts this time is EOT. n Before EOT n The engine shutdown time recorded is EOT n-1 …EOT1, and the array EOT [n] Is the engine shutdown time database composed of EOT1…EOT n .

[0038] Step S102: Obtain the range Δt in the array EOT [n] ;

[0039] Specifically, the range Δt is the absolute difference between the maximum engine shutdown time EOT [n] in the array EOT max and the minimum engine shutdown time EOT min . After obtaining the array EOT [n] , the engine control unit can obtain the maximum engine shutdown time EOT [n] and the minimum engine shutdown time EOT max from the array EOT min . Through a simple subtraction operation, the range Δt of the array EOT [n] can be obtained. It can be understood that the range Δt is a time value.

[0040] Step S103: If the range Δt meets the preset conditions, it is determined that there is an unreasonable fault in the shutdown timer.

[0041] In one embodiment, the set condition is that the range Δt is less than or equal to the set threshold t. That is to say, when the range Δt is less than or equal to the set threshold t, it is determined that there is an unreasonable fault in the stopwatch. Specifically, since there is a deviation within a certain range in the engine shutdown time during a certain number of consecutive engine start-stop cycles, by defining a certain number as the preset number n, and reasonably setting a certain range of deviation as the set threshold t, the fault diagnosis of the stopwatch is then carried out. If the range Δt is less than or equal to the set threshold t, it means that in the array EOT composed of the engine shutdown times of the consecutive preset number n of engine start-stop cycles [n] the cumulative time value of any two engine start-stop cycles is not higher than the set threshold t. When the range Δt is less than or equal to the set threshold t, it can be determined that there is an error in the engine shutdown times of the consecutive preset number n of engine start-stop cycles, and the engine control unit can conclude that there is an unreasonable fault in the stopwatch.

[0042] On the contrary, if the range Δt is greater than the set threshold t, it is determined that the stopwatch has no fault. When the range Δt is greater than the set threshold t, it means that in the array EOT composed of the engine shutdown times of the consecutive preset number n of engine start-stop cycles [n] there are at least two cumulative time values of engine start-stop cycles higher than the set threshold t. That is to say, during the consecutive preset number n of engine start-stop cycles of the engine, if there are at least two engine shutdown times in the start-stop cycles with a deviation of the set threshold t, it can be determined that the engine shutdown times of the preset number n are normal, and the engine control unit can conclude that the stopwatch has no fault.

[0043] It can be understood that the set threshold t is a time value, and the set threshold t can be set according to the preset number n or according to the diagnostic accuracy requirements. This application does not make a limitation here. After the set threshold t is determined, it is compared with the range Δt of the obtained array EOT [n] for size comparison.

[0044] Specifically, based on the size value of the range Δt of the array EOT [n] and the set threshold t, the engine control unit can draw a conclusion on whether there is an unreasonable fault in the stopwatch. It can be understood that an unreasonable fault in the stopwatch means that there is a numerical difference between the engine shutdown time feedback by the stopwatch and the cumulative time value under the actual engine start-stop cycle.

[0045] Using the diagnostic method disclosed in this embodiment to assist the shutdown timer chip in performing shutdown timer fault diagnosis can independently complete the shutdown timer fault diagnosis when the self-diagnosis function of the shutdown timer chip is abnormal. When there are unreasonable faults in the shutdown timer, it can ensure that the engine control unit can identify them in time. Moreover, only the engine shutdown time needs to be obtained, and fault diagnosis can be completed without adding sensors such as water temperature and air temperature. The diagnostic logic strategy is simple, the development cycle is short, and the development cost is low.

[0046] In one embodiment, the set threshold t is [0, 3] seconds.

[0047] Specifically, the set threshold t can be arbitrarily selected within [0, 3] seconds. For example, it can be 0s, 1s, 1.5s, 2s, 2.5s, 3s. When the set threshold t is 0 second, if the range Δt is equal to the set threshold t at this time, it means that [n] all the engine shutdown times in the array EOT are the same. When the set threshold t is 3 seconds, if the range Δt is less than or equal to the set threshold t at this time, it means that [n] the cumulative time value of any two engine start-stop cycles does not exceed 3 seconds. That is to say, if there is no deviation higher than 3 seconds among the engine shutdown times of the preset number n continuously, it can be determined that there is an error in the engine shutdown times of the preset number n, and the engine control unit can draw the conclusion that there is an unreasonable fault in the shutdown timer.

[0048] It can be understood that the set threshold t can be set according to the diagnostic accuracy. The lower the value of the set threshold t, to meet the set condition that the range Δt is less than or equal to the set threshold t, [n] the deviation values among the engine shutdown times in the array EOT need to be lower. And there are certain deviations among the engine shutdown times of the engine during the start-stop cycle. During normal use, only when the engine shutdown times fed back by the shutdown timer are incorrect can the set condition that the range Δt is less than or equal to the set threshold t be met. Therefore, the lower the value of the set threshold t, the higher the accuracy of the conclusion drawn by the engine control unit that there is an unreasonable fault in the shutdown timer.

[0049] In addition, the set threshold t can also be set according to the value of the preset number n. The larger the preset number n, it means that [n] the more engine shutdown time data in the array EOT, and [n] the greater the probability that the deviation values among the engine shutdown times in the array EOT are larger. When there is an unreasonable fault in the shutdown timer, [n]There may also be a large range Δt. For example, in the first few of the preset number of times n, the shutdown timer has no fault, and then the shutdown timer has an unreasonable fault and feedbacks the same EOT. When obtaining the array EOT [n] , the maximum engine shutdown time EOT max and the minimum engine shutdown time EOT min are still the EOTs feedback before the shutdown timer fails, resulting in a deviation of the range Δt from the set threshold t, causing the engine control unit to draw the wrong conclusion that the shutdown timer has no fault. At this time, the set value of the set threshold t can be appropriately increased to improve the diagnostic accuracy.

[0050] Furthermore, the smaller the preset number of times n, the fewer the engine shutdown time data in the array EOT [n] . The possibility that the deviation values among the engine shutdown time data in the array EOT [n] are smaller is relatively high. When the shutdown timer has no fault, the range Δt of the array EOT [n] may also be small. At this time, the set value of the set threshold t can be appropriately decreased to improve the diagnostic accuracy.

[0051] In one embodiment, the preset number of times n is [3, 5] times.

[0052] Specifically, the preset number of times n can be set according to actual diagnostic requirements. When the value of the preset number of times n is relatively large, correspondingly, the engine shutdown time data in the array EOT [n] is also more. When the engine control unit performs fault diagnosis, it needs to obtain the range Δt from the array EOT [n] . The huge engine shutdown time data reduces the diagnostic efficiency of the engine control unit, thus affecting the diagnostic completion rate.

[0053] Furthermore, when the value of the preset number of times n is relatively small, correspondingly, the engine shutdown time data in the array EOT [n] is also less. When the engine control unit performs fault diagnosis, it can only analyze the engine shutdown time of the engine in the recent few times. If the cumulative value of the start-stop cycle time of the engine within this preset number of times n is close, resulting in the array EOT [n] meeting the set condition that the range Δt is less than or equal to the set threshold t, the engine control unit will falsely report that the shutdown timer has an unreasonable fault. Therefore, in this embodiment, the preset number of times n is preferably controlled within [3, 5] times.

[0054] Furthermore, when the preset number of times n is 4 times, after the engine starts, it is equivalent to that the engine has just completed a start-stop cycle this time. The engine control unit obtains the previous 4 consecutive start-stop cycles including this start-stop cycle to form the array EOT[4] , at this time, the array EOT [n] has 4 engine shutdown times. If the range Δt of the array EOT [4] at this time is less than or equal to the set threshold t, it is equivalent that the deviation values between the engine shutdown times of 4 consecutive start-stop cycles including this start-stop cycle are all within the set threshold t, and the engine control unit can determine that there is an unreasonable fault in the shutdown timer.

[0055] In one embodiment, obtaining the array EOT including the engine shutdown times of a continuous preset number n [n] of steps includes multiple steps of obtaining EOT, that is, including respectively obtaining EOT1, EOT2, EOT3,... EOT n of steps.

[0056] Specifically, during the start-stop cycles of the engine for a continuous preset number n, the corresponding preset number n of engine shutdown times will be generated. Each time the engine starts and stops once, the cumulative value of the time recorded by the shutdown timer is the EOT of this start-stop cycle and is fed back to the engine control unit. During the continuous preset number n of start-stop cycles, the shutdown timer can respectively record its EOT and feed it back to the engine control unit. It can be understood that after the engine starts this time, the shutdown timer feeds back the cumulative value of the time of this engine shutdown cycle to the engine control unit, and the engine control unit starts to perform fault diagnosis on the shutdown timer. The cumulative value of the time fed back by the shutdown timer this time is the EOT n , and the cumulative value of the time recorded before EOT n is the EOT n-1 ... EOT1, and the engine control unit respectively records and stores EOT1... EOT n to form the array EOT [n] .

[0057] In one embodiment, the steps of obtaining EOT specifically include:

[0058] When the engine switches to the shutdown state, the shutdown timer starts timing;

[0059] Detect whether the diagnostic enable condition is met;

[0060] If the engine shutdown time meets the diagnostic enable condition, the shutdown timer stops timing and obtains EOT.

[0061] Specifically, after the engine has completed its current operation and entered the shutdown state, the shutdown timer starts to intervene at this time. The shutdown timer starts accumulating time from the time point when the engine shuts down. The time point when the engine shuts down is 0s. While the shutdown timer is accumulating time, it detects whether the diagnostic enabling condition is met. The components for detecting whether the diagnostic enabling condition is met are not limited to the shutdown timer itself, and this application does not make any limitations here. As long as the shutdown timer can obtain a signal that meets the diagnostic enabling condition and requires the timer to stop, the diagnostic enabling condition in this application is a condition set to make the shutdown timer stop timing. For example, it can be the range of the instantaneous current change value generated when the engine starts, or the information indicating that the engine is in the starting and running state, or any other condition that can indicate that the engine is at the starting time point, such as whether the detected shutdown timer signal is valid. The diagnostic enabling condition can be one or multiple. When there are multiple diagnostic enabling conditions, they can be conditions that must be met simultaneously, or conditions that only need to meet any one of them. This application does not make any limitations here.

[0062] It can be understood that according to the actually set diagnostic enabling condition, the shutdown timer determines whether to stop accumulating time based on the detection result. When it is determined that the time accumulation needs to end, the shutdown timer records the current time accumulation value. At this time, the time accumulation value is the engine shutdown time (EOT) of the engine's current start-stop cycle. The shutdown timer feeds back the engine shutdown time (EOT) of the engine's current start-stop cycle to the engine control unit.

[0063] Taking the diagnostic enabling condition that the engine switches to the running state and the shutdown timer signal is valid as an example, the shutdown timer starts accumulating time from the time point when the engine stops running with 0s as the starting point, continuously detecting whether the engine switches to the running state and whether the shutdown timer signal is valid. When it detects that the set diagnostic enabling condition is met, that is, it detects that the engine switches to the running state and at the same time can detect that the shutdown timer signal is valid, the shutdown timer needs to stop accumulating time. The shutdown timer stops timing and records the current time accumulation value as the EOT of the engine's current start-stop cycle, and at the same time feeds back the EOT of this engine start-stop cycle process to the engine control unit.

[0064] In one embodiment, after the step of the shutdown timer stops timing and obtains the engine shutdown time (EOT) when the diagnostic enabling condition is met, it further includes:

[0065] The EOT of the shutdown timer is cleared.

[0066] Specifically, when it is judged according to the diagnosis enabling condition that the engine is in the starting and running state time point, the shutdown timer stops accumulating time, and the accumulated time value recorded at this time is used as the EOT of this engine start-stop cycle process and fed back to the engine control unit. The engine control unit stores the EOT. The shutdown timer has completed the time accumulation of this engine start-stop cycle. Therefore, it is necessary to clear the current accumulated time value so that after the engine stops running next time, the shutdown timer can start accumulating time from 0s again.

[0067] It can be understood that after the steps of stopping the timing of the shutdown timer and obtaining the EOT when the diagnosis enabling condition is satisfied, clearing the EOT recorded by the shutdown timer can enable the shutdown timer to repeatedly record the engine shutdown time of the engine start-stop cycle process, so that the engine control unit can obtain the engine shutdown time for a continuous preset number n through the shutdown timer.

[0068] In one embodiment, the diagnosis enabling condition includes: the engine satisfies the first preset condition, and the shutdown timer satisfies the second preset condition.

[0069] It can be understood that the diagnosis enabling condition can be one or more, and the specific quantity can be set according to the actual situation, which is not limited in this application. For example, when the diagnosis enabling condition is two, one diagnosis enabling condition is that the engine satisfies the first preset condition, and the first preset condition indicates that the engine is at the time point of starting and running. For example, it can be detected that the engine is in the starting and running state, or it can be detected that the engine has a current within the starting current range, etc. Another diagnosis enabling condition is that the shutdown timer satisfies the second preset condition, and the second preset condition indicates that the shutdown timer is in the normal working state. For example, it is detected that the signal of the shutdown timer is valid, or it is continuously detected that the accumulated time value of the shutdown timer is increasing, etc.

[0070] Furthermore, by setting two diagnosis enabling conditions, it can be ensured that the EOT obtained by the engine control unit is valid, thereby ensuring the accuracy of the array EOT [n] Accordingly, in the diagnosis process, the conclusion of whether there is an unreasonable fault in the shutdown timer determined by the engine control unit will also be more accurate. That is to say, setting multiple preset conditions as the diagnosis enabling condition can effectively improve the reliability and accuracy of the diagnosis.

[0071] In one embodiment, the first preset condition is that the engine switches to the running state.

[0072] Specifically, the first preset condition for determining the engine state in the diagnosis enabling condition is that the engine is detected to have switched to the running state. It can be understood that detecting that the engine has switched to the running state means that the engine has ended this start-stop cycle, and the stopwatch needs to stop accumulating time, and the accumulated time value recorded at this time is fed back to the engine control unit to form the EOT of this start-stop cycle.

[0073] In one embodiment, the second preset condition is that the signal of the stopwatch is valid.

[0074] Specifically, the second preset condition for the working state of the stopwatch in the diagnosis enabling condition is that the signal of the stopwatch is detected to be valid.

[0075] It can be understood that when it is detected that the engine is at the starting and running time point, it is also necessary to simultaneously detect the working state of the stopwatch to ensure that the accumulated time value of the stopwatch is valid, so as to avoid incorrect data and prevent the engine control unit from drawing incorrect diagnostic conclusions.

[0076] It can be understood that when it is detected that the engine is in the starting and running stage, it must also be detected that the signal of the stopwatch is valid. Only at this time will the stopwatch end the time accumulation, and the accumulated time value at this moment will be fed back to the engine control unit to form the EOT of this engine start-stop cycle.

[0077] In a specific embodiment, please refer to Figure 2 , the diagnostic method includes the following steps:

[0078] Step S201: When the engine switches to the stop state, the stopwatch starts timing;

[0079] Specifically, when the engine switches to the stop state, the stopwatch starts accumulating time from 0s.

[0080] Step S202: Detect whether the engine has switched to the running state and whether the signal of the stopwatch is valid. If so, execute step S203; if not, repeat the step of detecting whether the engine has switched to the running state and whether the signal of the stopwatch is valid;

[0081] Step S203: The stopwatch stops timing, records the accumulated time value at this time as EOT and feeds it back to the engine control unit;

[0082] Step S204: The stopwatch clears the EOT;

[0083] Step S205: Determine whether the number of times the engine control unit stores the EOT reaches the preset number n. If so, execute step S206; if not, execute step S201;

[0084] Specifically, every time the engine stops and starts in a cycle, the stopwatch will feedback the EOT of the current stop-start cycle to the engine control unit through steps S201 to S204. After the number of engine stop-start cycles is greater than or equal to the preset number n, the engine control unit has also cumulatively stored the EOT of the preset number n. If the number of engine stop-start cycles is less than the preset number n, it is necessary to continue to cycle through steps S201 to S204 to increase the EOT database accumulated by the engine control unit. It can be understood that when the preset number n remains unchanged, after a certain engine stop-start cycle ends and the number of EOT stored in the engine control unit reaches the preset number n, then during the subsequent engine stop-start cycles, the number of EOT stored in the engine control unit must also meet the condition of reaching the preset number n.

[0085] Step S206: The engine control unit obtains the array EOT of consecutive engine shutdown times according to the preset number n [n] ;

[0086] Specifically, according to the set preset number n, the engine control unit automatically selects the most recent consecutive preset number n of engine shutdown times including the current engine stop-start cycle from the stored engine shutdown times during multiple consecutive stop-start cycles, and forms the array EOT [n] .

[0087] Step S207: Obtain the range Δt in the array EOT [n] ;

[0088] Step S208: Determine whether the range Δt is less than or equal to the set threshold t. If so, execute step S209; if not, execute step S210;

[0089] Step S209: Determine that there is an unreasonable fault in the stopwatch;

[0090] Step S210: Determine that the stopwatch has no fault.

[0091] The present application discloses a diagnostic method for a stopwatch. Using the diagnostic method disclosed in the present application, it assists the stopwatch chip to perform stopwatch fault diagnosis. When the stopwatch chip has an abnormality and fails to identify invalidity, it fully exerts the diagnostic function, increases the redundancy of stopwatch fault diagnosis, improves the overall accuracy of fault diagnosis, and compared with other supplementary diagnostic methods, the diagnostic logic strategy of the method disclosed in the present application is simple, the development cost is low, and the development cycle is short.

[0092] The various embodiments / implementation manners provided by the present application can be combined with each other without conflict.

[0093] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various modifications and variations can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A diagnostic method for a stopwatch, characterized in that, The described diagnostic method includes: Obtain an array EOT of engine off times including a continuous preset number n of times [n] ; Obtain the range Δt in the array EOT [n] ; If the range Δt meets the set condition, it is determined that there is an unreasonable fault in the shutdown timer; Among them, the set condition is that the range Δt is less than or equal to the set threshold t, the set threshold t is set according to the value of the preset number n, and the set value of the set threshold t is positively correlated with the set value of the preset number n.

2. The diagnostic method according to claim 1, wherein The set threshold t is [0, 3] seconds.

3. The diagnostic method according to claim 1, wherein The preset number n is [3, 5] times.

4. The diagnostic method according to claim 1, wherein The obtaining includes steps of obtaining an array EOT of engine off-time for a continuous preset number n of times, including a plurality of steps of obtaining EOT. [n] ​ 5. The diagnostic method according to claim 4, characterized in that, The step of obtaining the EOT specifically includes: When the engine switches to the shutdown state, the shutdown timer starts timing; Detect whether the diagnostic enable condition is met; If the diagnostic enable condition is met, the shutdown timer stops timing and obtains the EOT.

6. The diagnostic method according to claim 5, characterized in that, After the step that if the diagnostic enable condition is met, the shutdown timer stops timing and obtains the EOT, it further includes: The EOT of the shutdown timer is cleared.

7. The diagnostic method according to claim 5, wherein The diagnostic enable condition includes: the engine meets the first preset condition, and the shutdown timer meets the second preset condition.

8. The diagnostic method according to claim 7, wherein The first preset condition is that the engine switches to the running state.

9. The diagnostic method according to claim 7, characterized in that, The second preset condition is that the signal of the shutdown timer is valid.

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