Method and device for preventing misfire false positives in a switch-ox extended range vehicle

Abstract

The application discloses a method for preventing misreporting of misfire of a range-extender vehicle based on switch oxygen, and the method comprises the following steps: judging whether an auxiliary misfire judgment function is opened; if the auxiliary misfire judgment function is not opened, opening a misfire detection function; if the auxiliary misfire judgment function is opened, judging whether the following conditions are met: N real (t)' is greater than a first threshold value, N real (t)' represents a filtered motor measured torque change gradient; if the conditions are not met, the misfire detection function is closed; if the conditions are met, judging whether the following conditions are met: N real (t)' is greater than a first threshold value for more than a second threshold value of times; if the conditions are met, the misfire detection function is opened; if the conditions are not met, the misfire detection function is closed. The application further discloses a device for preventing misreporting of misfire of a range-extender vehicle based on switch oxygen, comprising a first judgment module, a second judgment module, a first control module and a second control module, and the device can solve the problem of misreporting of misfire faults of the range-extender vehicle based on switch oxygen due to interference of a motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle misfire detection, in particular to a method and device for preventing misfire false alarm of a range-extender vehicle based on switching oxygen. BACKGROUND

[0002] When the engine is working normally, the crankshaft has an acceleration and deceleration process due to the compression and work strokes. Misfire will cause the misfire cylinder to fail to work normally, resulting in a lack of acceleration process for the engine, and a large speed fluctuation. Therefore, most vehicle models can diagnose whether misfire failure occurs by analyzing the irregularity of speed fluctuation through the crankshaft position sensor. However, for range-extender vehicles based on switching oxygen sensors, it is impossible to accurately know the air-fuel ratio, the engine only generates electricity, and is hard connected with the motor. When the motor control is unreasonable, abnormal fluctuation of the motor speed may cause abnormal fluctuation of the crankshaft angular acceleration, eventually leading to a non-real misfire signal during normal driving, triggering a misfire failure of the cylinder cut-off and the engine cannot be restarted. The customer may run out of electricity when the range-extender cannot generate electricity during high-speed driving. SUMMARY

[0003] In view of the above problems of the prior art, the present application aims to provide a method and device for preventing misfire false alarm of a range-extender vehicle based on switching oxygen, which can prevent misfire false alarm caused by motor interference.

[0004] To solve the above technical problems, one technical scheme of the present application is to provide a method for preventing misfire false alarm of a range-extender vehicle based on switching oxygen, comprising the following steps:

[0005] determining whether to open an auxiliary misfire determination function;

[0006] if the auxiliary misfire determination function is not opened, opening a misfire detection function;

[0007] if the auxiliary misfire determination function is opened, determining whether the following conditions are met: real the filtered motor measured torque change gradient (t)' is greater than a first threshold value, and N real (t)' represents the filtered motor measured torque change gradient;

[0008] if not, closing the misfire detection function;

[0009] if yes, determining whether the following conditions are met: real the number of times that the filtered motor measured torque change gradient (t)' is greater than the first threshold value within a certain period is greater than a second threshold value;

[0010] if not, closing the misfire detection function;

[0011] if yes, opening the misfire detection function.

[0012] Further, the filtered motor measured torque change gradient N real (t)' is obtained by the following equation:

[0013]

[0014] In equation (I), N real' represents the filtered motor measured torque, N modle' represents the filtered engine model torque.

[0015] Further, the filtered motor measured torque N real' is obtained by the following equation:

[0016] N real' = N real” + N real *(N real -N real” )*K (II)

[0017] In equation (I), N real” represents the previous time motor measured torque value, N real represents the current motor measured torque value, and K represents a filter coefficient.

[0018] The filtered engine model torque N modle' is obtained by the following equation:

[0019] N modle' = N modle” + N modle *(N modle -N modle” )*K (III)

[0020] In equation (III), N modle” represents the previous time engine model torque, N modle represents the current engine model torque.

[0021] Further, the motor measured torque N real is obtained by the following equation:

[0022]

[0023] In equation (IV), p represents motor power, and n represents motor speed.

[0024] The engine model torque N modle is obtained by the following equation:

[0025] N modle = N miopt *etazwist (V)

[0026] In formula (V), N miopt represents the optimal torque of the current operating point, and etazwist represents the ignition angle efficiency.

[0027] Further, in the step of judging whether to open the auxiliary misfire determination function, the following sub-steps are included:

[0028] judging whether the current operating condition is a problem operating condition;

[0029] If not, the auxiliary misfire determination function is not opened;

[0030] If yes, motor-related information is obtained, and it is judged whether the motor-related information meets a preset condition;

[0031] If not, the auxiliary misfire determination function is not opened;

[0032] If yes, it is judged whether the number of misfires is greater than a third threshold value and N real is greater than a fourth threshold value;

[0033] If not, the auxiliary misfire determination function is not opened;

[0034] If yes, the auxiliary misfire determination function is opened.

[0035] Further, in the step of judging whether the current operating condition is a problem operating condition, the following sub-steps are included:

[0036] obtaining an engine speed and an engine load;

[0037] judging whether the engine speed meets a condition of being greater than a fifth threshold value and being less than a sixth threshold value;

[0038] If not, it is judged that the current operating condition is not a problem operating condition;

[0039] If yes, it is judged whether the engine load meets a condition of being greater than a seventh threshold value and being less than an eighth threshold value;

[0040] If not, it is judged that the current operating condition is not a problem operating condition;

[0041] If yes, it is judged that the current operating condition is a problem operating condition.

[0042] Further, the motor-related information includes a motor temperature, a motor current, a motor voltage, a motor speed, and a motor communication signal.

[0043] Further, the specific method of judging whether the motor-related information meets the preset condition is:

[0044] Determining whether the motor temperature is less than a ninth threshold according to the motor temperature;

[0045] Determining whether the motor current satisfies the condition that the motor current is greater than a tenth threshold value and less than an eleventh threshold value according to the motor current;

[0046] determining, based on the motor voltage, whether the motor voltage satisfies a condition that the motor voltage is greater than a twelfth threshold value and less than a thirteenth threshold value;

[0047] According to the motor speed, it is determined whether the N real When the load is greater than or equal to 100N, Less than the fourteenth threshold; when N real When the load is less than 100N, |N real -N modle |Less than the fifteenth threshold;

[0048] Determining whether the communication between the motor and the engine is normal according to the motor communication signal;

[0049] If all of the above conditions are met, it is determined that the motor-related information meets the preset conditions; otherwise, it is determined that the motor-related information does not meet the preset conditions.

[0050] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a device for preventing false fire alarms of extended-range vehicles based on switching oxygen, comprising:

[0051] The first judgment module is used to judge whether to turn on the auxiliary misfire judgment function;

[0052] a second judgment module, configured to judge whether to turn on the misfire detection function when the first judgment module judges to turn on the auxiliary misfire determination function;

[0053] The first control module is configured to turn on the auxiliary misfire determination function when the first judgment module determines that the auxiliary misfire determination function is turned on; and turn off the auxiliary misfire determination function when the first judgment module determines that the auxiliary misfire determination function is not turned on.

[0054] a second control module, configured to enable the misfire detection function when the first control module disables the auxiliary misfire determination function; enable the misfire detection function when the second determination module determines that the misfire detection function should be enabled; and disable the misfire detection function when the second determination module determines that the misfire detection function should not be enabled.

[0055] Furthermore, the first judgment module includes the following submodules:

[0056] The first judgment submodule is used to judge whether the current working condition is a problem working condition;

[0057] a second judgment submodule, configured to judge whether the motor-related information meets a preset condition based on the acquired motor-related information when the first judgment submodule determines that the current operating condition is a problem operating condition;

[0058] The third judgment submodule is used to judge whether the number of misfires is greater than the third threshold and N real Greater than the fourth threshold.

[0059] The method and device for preventing false fire alarms in a range-extended vehicle based on switching oxygen of the present invention have at least the following beneficial effects: the motor speed is introduced to reversely calculate the motor's measured torque, and further the absolute value of the difference between the filtered motor's measured torque and the filtered engine model torque within a certain period is calculated to the ratio of the filtered model torque within the period, and the change gradient of the motor's measured torque. This assists in determining whether a misfire is real, and only when it is determined to be a real misfire is misfire detection performed, thereby avoiding false fire alarms caused by unreasonable motor control. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0061] Figure 1 The present invention is a flow chart of an embodiment of a method for preventing false fire alarms in a range-extended vehicle based on switching oxygen.

[0062] Figure 2 for Figure 1 Flowchart of step S100 in FIG.

[0063] Figure 3 for Figure 2 Flowchart of step S110 in FIG.

[0064] Figure 4 The present invention is a structural block diagram of a device for preventing false fire alarms in a range-extended vehicle based on switching oxygen. DETAILED DESCRIPTION

[0065] The present invention will be further described below with reference to the accompanying drawings.

[0066] The range extender in the switch oxygen-based range extended vehicle is responsible for driving the generator to rotate, the generator generates electricity and delivers to the drive motor, and the drive motor drives the tire. The addition of the motor makes the engine speed lower or the shaft hardware problem resonance produces torque interference, resulting in the engine speed signal obtained by the electronic control unit cannot reflect the real engine speed fluctuation, and then causes misfire signal distortion to bring misfire misjudgment or omission. The switch oxygen sensor produces a corresponding voltage to the electronic control unit by sensing the change of oxygen concentration on the exhaust side, which can only reflect the air-fuel ratio of 0.98-1.02, and cannot perceive the actual air-fuel ratio like the wideband oxygen sensor to determine whether the engine is a true misfire, so the signal of the motor needs to be introduced to assist in judgment.

[0067] Referring to Figure 1 The flow chart of the method for preventing misfire misreporting of the switch oxygen-based range extended vehicle of the present application is shown in FIG. 1. The embodiment specifically includes the following steps:

[0068] S100, determining whether to open the auxiliary misfire judgment function.

[0069] Referring to Figure 2 , the step S100 includes the following sub-steps:

[0070] S110, determining whether the current working condition is a problem working condition.

[0071] In the embodiment, the working condition prone to misreporting misfire fault is defined in advance, when the working condition is met, misfire misreporting is prone to occur, so at this time it is necessary to further determine whether to open the auxiliary misfire judgment function to determine whether it is a true misfire, but if it is not the working condition prone to misreporting misfire fault, the auxiliary misfire judgment function can be skipped and the normal misfire detection can be directly performed.

[0072] Referring to Figure 3 , the step S110 includes the following sub-steps:

[0073] S111, obtaining the engine speed and engine load.

[0074] S112, determining whether the engine speed meets the condition of being greater than the fifth threshold value and less than the sixth threshold value.

[0075] In the embodiment, the fifth threshold value is 2000 rpm, and the sixth threshold value is 5000 rpm. According to the vehicle misfire detection signal, it can be judged that the engine speed in the interval of 2000 rpm-5000 rpm is prone to misreporting misfire.

[0076] S113, if not met, determining that the current working condition is not a problem working condition.

[0077] S114, if met, determining whether the engine load meets the condition of being greater than the seventh threshold value and less than the eighth threshold value.

[0078] In this embodiment, the seventh threshold value is 40%, and the eighth threshold value is 120%. According to the vehicle misfire detection signal, it can be determined that the engine load is in the interval of 40%-120% and is prone to misreporting misfire.

[0079] S115, if not, it is determined that the current working condition is not a problem working condition.

[0080] S116, if yes, it is determined that the current working condition is a problem working condition.

[0081] Only when the engine speed and load meet the above conditions at the same time, the current working condition meets the pre-set problem working condition.

[0082] S120, if not, the auxiliary misfire determination function is not opened.

[0083] S130, if yes, the motor related information is obtained, and it is determined whether the motor related information meets the pre-set condition.

[0084] The motor related information includes motor temperature, motor current, motor voltage, motor speed and motor communication signal.

[0085] The specific method for determining whether the motor related information meets the pre-set condition is:

[0086] According to the motor temperature, it is determined whether the motor temperature is less than the ninth threshold value, and in this embodiment, the ninth threshold value is 90 degrees Celsius; according to the motor current, it is determined whether the motor current is greater than the tenth threshold value and less than the eleventh threshold value, and in this embodiment, the tenth threshold value is 175A and the eleventh threshold value is 400A; according to the motor voltage, it is determined whether the motor voltage is greater than the twelfth threshold value and less than the thirteenth threshold value, and in this embodiment, the twelfth threshold value is 350V and the thirteenth threshold value is 800V; according to the motor speed, it is determined whether N real is greater than or equal to 100N, is less than the fourteenth threshold value, N real represents the measured torque of the motor, N modle represents the engine model torque, and in this embodiment, the fourteenth threshold value is 5%; when N real is less than 100N, |N real -N modle is less than the fifteenth threshold value, and in this embodiment, the fifteenth threshold value is 5N; according to the motor communication signal, it is determined whether the motor and the engine communication is normal. If no signal is detected on the controller area network, it means that the signal is lost, and at this time the motor and the engine cannot communicate normally.

[0087] The motor measured torque N real is obtained by the formula where p represents the motor power, and n represents the motor rotation speed; the engine model torque N modle By formula N modle = N miopt *etazwist, where N miopt represents the optimal torque of the current operating point, the engine bench adjusts the variable valve timing and the ignition angle at each operating point to obtain the optimal torque of the current operating point, and etazwist represents the ignition angle efficiency, which can be directly read from data.

[0088] If all the above conditions are met, it is determined that the motor related information meets the preset condition, otherwise, it is determined that the motor related information does not meet the preset condition. That is, the motor temperature, current and voltage are required to be within a reasonable range, the motor torque accuracy meets the requirements, and the motor and engine communication is normal.

[0089] S140, if not, the auxiliary misfire determination function is not opened.

[0090] S150, if yes, it is determined whether the number of misfires is greater than a third threshold value and N real is greater than a fourth threshold value.

[0091] When the number of misfires is greater than the third threshold value, the number of misfires is large, which is easy to cause false misfire faults, and the auxiliary misfire determination function needs to be opened, otherwise, the influence on false misfire faults is small, and the conventional misfire detection can be directly performed. In the embodiment, the fourth threshold value is 50 N, misfire will cause the misfire cylinder to be unable to normally work, so that the engine lacks a normal acceleration process, causing large speed fluctuation, and causing large torque fluctuation, so whether misfire fault occurs can be diagnosed by analyzing the irregularity of speed fluctuation of the crankshaft position sensor. When the torque is less than 50 N, the fluctuation will not be too large, and the diagnosis of misfire fault will not be affected, so the torque is set to be greater than 50 N to open the auxiliary misfire determination function.

[0092] S160, if not, the auxiliary misfire determination function is not opened.

[0093] S170, if yes, the auxiliary misfire determination function is opened.

[0094] S200, if the auxiliary misfire determination function is not opened, the misfire detection function is opened.

[0095] When the misfire detection function is opened to perform the conventional misfire detection, the number of misfires is also counted, and the number of misfires detected in each ignition counting period is counted, wherein the counted number of misfires is cleared at the end of the counting period, and the counted number of misfires can be used in the S150 step to determine whether the auxiliary misfire determination function is opened.

[0096] S300, if the auxiliary misfire detection function is turned on, determine whether N real (t)' is greater than a first threshold value, N real (t)' represents the filtered motor measured torque change gradient.

[0097] The torque is fluctuating, not a fixed value, and a more stable value can be obtained by filtering.

[0098] The filtered motor measured torque change gradient N real (t)' is obtained by the formula , N real' represents the filtered motor measured torque, N modle' represents the filtered engine model torque, and in this embodiment, the first threshold value is 50%.

[0099] The filtered motor measured torque N real' is obtained by the formula N real' = N real” +N real *(N real -N real” )*K, N real” represents the previous motor measured torque value, N real represents the current motor measured torque value, and K represents the filtering coefficient; the filtered engine model torque N modle' is obtained by the formula N modle' = N modle” +N modle *(N modle -N modle” )*K, N modle” represents the previous engine model torque, N modle represents the current engine model torque, and K represents the filtering coefficient. The previous motor measured torque value N real” and the current motor measured torque value N real are both motor measured torques, and their calculation methods are the same as those of the aforementioned motor measured torque. The previous engine model torque N modle” and the current engine model torque N modle are both engine model torques, and their calculation methods are the same as those of the aforementioned engine model torque, which will not be repeated here.

[0100] S400, if not, turn off the misfire detection function.

[0101] S500, if yes, determine whether the filtered motor measured torque change gradient N real (t)' is greater than a first threshold value more than a second threshold value.

[0102] S600, if not, then closing the misfire detection function.

[0103] S700, if yes, then opening the misfire detection function.

[0104] In the embodiment, when the absolute value of the difference between the filtered motor measured torque and the filtered engine model torque in a certain period and the filtered model torque in the period is greater than 50%, and the number of times that the motor measured torque change gradient exceeds 50% is monitored in 1000 combustion is more than 40, it means real misfire, then open the misfire detection function to detect misfire, and count the number of misfires; otherwise, it is not a real misfire, and the misfire detection function is closed to prevent misfire false alarm, and the number of misfires is not counted.

[0105] Referring to Figure 4 The structure block diagram of the application is shown in the figure. The misfire false alarm prevention device based on switch oxygen of the extended range electric vehicle includes:

[0106] The first judgment module 100 is used to judge whether to open the auxiliary misfire detection function.

[0107] In the embodiment, the first judgment module 100 includes the following sub-modules:

[0108] The first judgment sub-module 110 is used to judge whether the current working condition is a problem working condition.

[0109] The method for judging whether the current working condition is a problem working condition is as follows:

[0110] The engine speed and the engine load are obtained.

[0111] It is judged whether the engine speed meets the condition of being greater than the fifth threshold value and less than the sixth threshold value.

[0112] If not, it is judged that the current working condition is not a problem working condition.

[0113] If yes, it is judged whether the engine load meets the condition of being greater than the seventh threshold value and less than the eighth threshold value.

[0114] If not, it is judged that the current working condition is not a problem working condition.

[0115] If yes, it is judged that the current working condition is a problem working condition.

[0116] The second judgment sub-module 120 is used to judge whether the motor related information meets the preset condition based on the obtained motor related information when the first judgment sub-module 110 judges that the current working condition is a problem working condition.

[0117] The motor-related information includes motor temperature, motor current, motor voltage, motor speed and motor communication signal.

[0118] The method for determining whether the motor-related information meets the preset conditions is:

[0119] Determining whether the motor temperature is less than a ninth threshold according to the motor temperature;

[0120] Determining whether the motor current satisfies the condition that the motor current is greater than a tenth threshold value and less than an eleventh threshold value according to the motor current;

[0121] determining, based on the motor voltage, whether the motor voltage satisfies a condition that the motor voltage is greater than a twelfth threshold value and less than a thirteenth threshold value;

[0122] According to the motor speed, it is determined whether the N real When the load is greater than or equal to 100N, Less than the fourteenth threshold; when N real When the load is less than 100N, |N real -N modle |Less than the fifteenth threshold;

[0123] Determining whether the communication between the motor and the engine is normal according to the motor communication signal;

[0124] If all of the above conditions are met, it is determined that the motor-related information meets the preset conditions; otherwise, it is determined that the motor-related information does not meet the preset conditions.

[0125] The third judgment submodule 130 is used to judge whether the number of misfires is greater than the third threshold and N real Greater than the fourth threshold.

[0126] The second judgment module 200 is configured to judge whether the misfire detection function is turned on when the first judgment module 100 judges that the auxiliary misfire determination function is turned on.

[0127] In this embodiment, the second determination module 200 includes the following submodules:

[0128] The fourth judgment submodule 210 is used to judge whether the motor torque variation gradient N after filtering is satisfied. real (t)' is greater than the first threshold.

[0129] The fifth judgment submodule 220 is used to judge whether the filtered motor torque change gradient N is satisfied within a certain period. real The number of times (t)' is greater than the first threshold is greater than the second threshold.

[0130] The first control module 300 is configured to open the auxiliary determination misfire function when the first determination module 100 determines to open the auxiliary determination misfire function, and close the auxiliary determination misfire function when the first determination module 100 determines not to open the auxiliary determination misfire function.

[0131] The second control module 400 is configured to open the misfire detection function when the first control module 300 closes the auxiliary determination misfire function, open the misfire detection function when the second determination module 200 determines to open the misfire detection function, and close the misfire detection function when the second determination module 200 determines not to open the misfire detection function.

[0132] When the first determination submodule 110 determines that the current working condition is not the problem working condition, the second determination submodule 120 determines that the motor related information does not meet the preset condition, and / or the third determination submodule 130 determines that the number of misfires is not greater than the third threshold value and N real (t)' is greater than the fourth threshold value, the first determination module 100 determines not to open the auxiliary determination misfire function, the first control module 300 closes the auxiliary determination misfire function, and the second control module 400 opens the misfire detection function at this time; when the first determination submodule 110 determines that the current working condition is the problem working condition, the second determination submodule 120 determines that the motor related information meets the preset condition, and the third determination submodule 130 determines that the number of misfires is greater than the third threshold value and N real (t)' is greater than the fourth threshold value, the first determination module 100 determines not to open the auxiliary determination misfire function, the first control module 300 closes the auxiliary determination misfire function, and the second control module 400 opens the misfire detection function at this time; when the first determination submodule 110 determines that the current working condition is the problem working condition, the second determination submodule 120 determines that the motor related information meets the preset condition, and the third determination submodule 130 determines that the number of misfires is greater than the third threshold value and N real (t)' is greater than the fourth threshold value, the first determination module 100 determines not to open the auxiliary determination misfire function, the first control module 300 closes the auxiliary determination misfire function, and the second control module 400 opens the misfire detection function at this time; when the first determination submodule 110 determines that the current working condition is the problem working condition, the second determination submodule 120 determines that the motor related information meets the preset condition, and the third determination submodule 130 determines that the number of misfires is greater than the third threshold value and N real (t)' is greater than the fourth threshold value, the first determination module 100 determines not to open the auxiliary determination misfire function, the first control module 300 closes the auxiliary determination misfire function, and the second control module 400 opens the misfire detection function at this time; when the first determination submodule 110 determines that the current working condition is the problem working condition, the second determination submodule 120 determines that the motor related information meets the preset condition, and the third determination submodule 130 determines that the number of misfires is greater than the third threshold value and N real (t)' is greater than the fourth threshold value, the first determination module 100 determines not to open the auxiliary determination misfire function, the first control module 300 closes the auxiliary determination misfire function, and the second control module 400 opens the misfire detection function at this time; when the first determination submodule 110 determines that the current working condition is the problem working condition, the second determination submodule 120 determines that the motor related information meets the preset condition, and the third determination submodule 130 determines that the number of misfires is greater than the third threshold value and N real (t)' is greater than the fourth threshold value, the first determination module 100 determines not to open the auxiliary determination misfire function, the first control module 300 closes the auxiliary determination misfire function, and the second control module 400 opens the misfire detection function at this time; when the first determination submodule 110 determines that the current working condition is the problem working condition, the second determination submodule 120 determines that the motor related information meets the preset condition, and the third determination submodule 130 determines that the number of misfires is greater than the third threshold value and N

[0133] The application determines the working condition that is easy to cause misfire false alarm by judging the problem working condition and motor related information, designs an auxiliary misfire judgment function for the working condition to determine whether it is real misfire, introduces the motor speed into the auxiliary misfire judgment function to inversely calculate the motor measured torque, further calculates the ratio of the absolute value of the difference between the filtered motor measured torque and the filtered engine model torque in a certain period and the filtered model torque in the period, the change gradient of the motor measured torque, and the two dimension parameters to assist in determining whether it is real misfire, and when it is determined to be real misfire, the misfire detection is carried out, so that the misreporting misfire fault caused by unreasonable motor control can be avoided.

Claims

1. A method for preventing false fire alarms in a range-extended vehicle based on switching oxygen, characterized in that: The following steps are involved: Determine whether to turn on the auxiliary misfire determination function; If the auxiliary misfire determination function is not turned on, the misfire detection function is turned on; If the auxiliary misfire determination function is turned on, it is determined whether N real (t)' is greater than the first threshold, N real (t)' represents the gradient of the motor torque measured after filtering; If not satisfied, the fire detection function is turned off; If it is satisfied, then determine whether N is monitored within a certain period. real (t)' is greater than the first threshold number of times greater than the second threshold; If not satisfied, the fire detection function is turned off; If so, the fire detection function is turned on.

2. The method for preventing false fire alarms in a range-extended vehicle based on switching oxygen according to claim 1, characterized in that: The filtered motor measured torque change gradient N real (t)' is obtained by the following formula: In formula (1), N real' Represents the measured torque of the motor after filtering, N modle' Represents the filtered engine model torque.

3. The method for preventing false fire alarms in a range-extended vehicle based on switching oxygen according to claim 2, characterized in that: The filtered motor measured torque N real' Obtained by the following formula: N real' = N real” + N real *(N real - N real” )*K (Two) In formula (2), N real” Indicates the actual torque value of the motor at the last moment, N real Indicates the current measured torque value of the motor, and K indicates the filter coefficient; The filtered engine model torque N modle' Obtained by the following formula: N modle' = N modle” + N modle *(N modle - N modle” )*K(III) In formula (3), N modle” Indicates the engine model torque at the last moment, N modle Indicates the current engine model torque.

4. The method for preventing false fire alarms in a range-extended vehicle based on switching oxygen according to claim 3, characterized in that: The motor measured torque N real Obtained by the following formula: In formula (4), p represents the motor power and n represents the motor speed; The engine model torque N modle Obtained by the following formula: N modle =N miopt *etazwist(five) In formula (5), N miopt It represents the optimal torque at the current operating point, and etazwist represents the ignition angle efficiency.

5. The method for preventing false fire alarms in a range-extended vehicle based on switching oxygen according to claim 1, characterized in that: The step of determining whether to turn on the auxiliary misfire determination function includes the following sub-steps: Determine whether the current working condition is a problem condition; If not, the auxiliary misfire determination function is not turned on; If yes, obtain motor-related information and determine whether the motor-related information meets the preset conditions; If not, the auxiliary misfire determination function is not turned on; If it is satisfied, then determine whether the number of misfires is greater than the third threshold and N real greater than a fourth threshold; If not, the auxiliary misfire determination function is not turned on; If the conditions are met, the auxiliary misfire determination function is turned on.

6. The method for preventing false fire alarms in a range-extended vehicle based on switching oxygen according to claim 5, characterized in that: The step of determining whether the current operating condition is a problematic operating condition includes the following sub-steps: Obtain engine speed and engine load; determining whether the engine speed satisfies a condition greater than a fifth threshold and less than a sixth threshold; If not, the current working condition is judged not to be a problem condition; If so, determining whether the engine load satisfies a condition greater than a seventh threshold and less than an eighth threshold; If not, the current working condition is judged not to be a problem condition; If it is satisfied, the current working condition is judged to be a problematic working condition.

7. The method for preventing false fire alarms in a range-extended vehicle based on switching oxygen according to claim 5, characterized in that: The motor-related information includes motor temperature, motor current, motor voltage, motor speed and motor communication signal.

8. The method for preventing false fire alarms in a range-extended vehicle based on switching oxygen according to claim 7, characterized in that: The specific method for determining whether the motor-related information meets the preset conditions is: Determining whether the motor temperature is less than a ninth threshold according to the motor temperature; Determining whether the motor current satisfies the condition that the motor current is greater than a tenth threshold value and less than an eleventh threshold value according to the motor current; determining, based on the motor voltage, whether the motor voltage satisfies a condition that the motor voltage is greater than a twelfth threshold value and less than a thirteenth threshold value; According to the motor speed, it is determined whether the N real When the load is greater than or equal to 100N, Less than the fourteenth threshold; when N real When the load is less than 100N, |N real -N modle |Less than the fifteenth threshold; Determining whether the communication between the motor and the engine is normal according to the motor communication signal; If all of the above conditions are met, it is determined that the motor-related information meets the preset conditions; otherwise, it is determined that the motor-related information does not meet the preset conditions.

9. A device for preventing false fire alarms in a range-extended vehicle based on switching oxygen, characterized in that: include: The first judgment module is used to judge whether to turn on the auxiliary misfire judgment function; a second judgment module, configured to judge whether to turn on the misfire detection function when the first judgment module judges to turn on the auxiliary misfire determination function; a first control module, configured to turn on the auxiliary misfire determination function when the first determination module determines that the auxiliary misfire determination function is turned on, and turn off the auxiliary misfire determination function when the first determination module determines that the auxiliary misfire determination function is not turned on; a second control module, configured to enable the misfire detection function when the first control module disables the auxiliary misfire determination function; enable the misfire detection function when the second determination module determines that the misfire detection function is enabled; and disable the misfire detection function when the second determination module determines that the misfire detection function is not enabled; The first judgment module includes the following submodules: The first judgment submodule is used to judge whether the current working condition is a problem working condition; a second judgment submodule, configured to judge whether the motor-related information meets a preset condition based on the acquired motor-related information when the first judgment submodule determines that the current operating condition is a problem operating condition; The third judgment submodule is used to judge whether the number of misfires is greater than the third threshold and N real Greater than the fourth threshold, where N real Indicates the current measured torque value of the motor.

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