An engine fault handling method for a heavy hybrid system

Abstract

The present invention discloses a method for handling engine faults in a heavy-duty hybrid system, comprising: determining the engine fault level; if the fault level is level one, monitoring whether the power system can operate normally by using the engine response torque; if the fault level is level two, determining the actual torque limit level by using the engine response torque, and switching the driving mode according to the actual limit state; if the fault level is level three, switching the driving mode to pure electric driving and stopping the engine; if the fault level is level four, activating the driving performance limit and limiting the power output of the engine or motor according to the torque; and if the fault level is level five, activating the driving performance limit and limiting the power output of the engine or motor according to the vehicle speed. The method for handling engine faults in a heavy-duty hybrid system of the present invention can not only handle engine faults by adjusting the heavy-duty hybrid system according to the current state, but also protect other power components from damage caused by the engine fault, and meet the regulatory restrictions for heavy-duty vehicles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heavy hybrid electric vehicles, more particularly, to an engine fault handling method of a heavy hybrid electric system. BACKGROUND

[0002] Heavy-duty vehicles refer to M or N class vehicles with a maximum total mass greater than 3500 kg. Hybrid electric vehicles refer to vehicles whose driving system is composed of two or more single driving systems that can operate simultaneously. Typically, a traditional internal combustion engine and an electric motor are used as power sources, and the vehicle's form power is provided independently or jointly by the single driving systems according to the actual vehicle driving state.

[0003] GB 17691-2018 standard specifies the emission limits and test methods for gaseous and particulate pollutants emitted by vehicles equipped with compression ignition engines in the sixth phase. The heavy-duty hybrid system uses a hybrid power combination to provide power while meeting the GB 17691 emission regulation limits. Currently, there is no engine fault handling method that meets the emission regulation.

[0004] Therefore, there is an urgent need for an engine fault handling method for a heavy hybrid electric system. SUMMARY

[0005] The purpose of the present application is to provide an engine fault handling method for a heavy hybrid electric system to solve the problems in the prior art. The method can handle engine faults by adjusting the heavy-duty hybrid electric system according to the current state, protect the remaining power components from damage caused by engine failure, and meet the heavy-duty vehicle regulation limits.

[0006] The present application provides an engine fault handling method for a heavy hybrid electric system, which comprises:

[0007] determining the fault level of the engine;

[0008] if the engine fault level is level one, monitoring whether the power system can work normally through the response torque of the engine;

[0009] if the engine fault level is level two, determining the actual torque limiting level through the response torque of the engine, and switching the driving mode according to whether the actual limiting state can meet the driver's demand;

[0010] if the engine fault level is level three, forcibly switching the driving mode to pure electric driving and stopping the engine from running;

[0011] if the engine fault level is level four, activating the driving performance limiting system and limiting the power output of the engine or the electric motor according to the torque;

[0012] If the engine failure level is five, the driving performance limiting system is activated, and the power output of the engine or the electric motor is limited according to the vehicle speed.

[0013] The engine failure handling method of the heavy hybrid power system as described above, wherein preferably, in the case that the engine failure level is one, the monitoring of whether the power system can work normally through the response torque of the engine specifically comprises:

[0014] When the engine has a one-level failure, the corresponding fault code is kept in the electronic control unit;

[0015] The electronic control unit sends the failure level to the vehicle control unit;

[0016] The vehicle control unit monitors whether the power system can work normally through the response torque of the engine after receiving the one-level failure of the engine;

[0017] If the power system can work normally, the current power output state is maintained;

[0018] The electronic control unit lights up the engine failure indicator light of the instrument to remind the driver to perform vehicle maintenance after the current driving cycle is completed.

[0019] The engine failure handling method of the heavy hybrid power system as described above, wherein preferably, in the case that the engine failure level is two, the judging of the actual torque limiting level through the response torque of the engine and the switching of the driving mode according to whether the actual limiting state can meet the demand of the driver specifically comprises:

[0020] When the engine has a two-level failure, the corresponding fault code is kept in the electronic control unit;

[0021] The electronic control unit sends the failure level to the vehicle control unit;

[0022] The vehicle control unit judges the actual torque limiting level through the response torque of the engine after receiving the two-level failure of the engine, and determines whether to maintain the current working condition according to the actual torque limiting level;

[0023] The vehicle control unit controls the instrument to give a text prompt of the engine failure;

[0024] The electronic control unit lights up the engine failure indicator light of the instrument to remind the driver to perform vehicle maintenance after the current driving cycle is completed.

[0025] The engine failure handling method of the heavy hybrid power system as described above, wherein preferably, the vehicle control unit judges the actual torque limiting level through the response torque of the engine after receiving the two-level failure of the engine, and determines whether to maintain the current working condition according to the actual torque limiting level, specifically comprising:

[0026] confirming that the current driving mode is in series mode or parallel mode;

[0027] if the current driving mode is in series mode, the vehicle controller obtains the driving demand of the driver;

[0028] the vehicle controller determines whether the maximum torque of the actual restriction state meets the driving demand;

[0029] if yes, the current mode is maintained;

[0030] if no, the vehicle controller determines whether the electric motor and the battery power meet the parallel mode;

[0031] if yes, the driving mode is switched to pure electric driving, and the vehicle controller controls the instrument to remind the driver of the driving mode switching;

[0032] if no, the current mode is maintained.

[0033] The engine fault handling method of the heavy hybrid power system as described above, preferably, in the case of a third level of engine fault, the driving mode is forcibly switched to pure electric driving, and the engine operation is stopped, specifically comprising:

[0034] when the engine has a third level of fault, the corresponding fault code is retained in the electronic control unit;

[0035] the electronic control unit sends the fault level to the vehicle controller;

[0036] the vehicle controller obtains the driving demand of the driver after receiving the third level of engine fault;

[0037] the vehicle controller determines whether the current power and the electric motor state meet the parallel mode;

[0038] if yes, the driving mode is forcibly switched to pure electric driving, and the engine operation is stopped;

[0039] if no, the vehicle operation is stopped;

[0040] the vehicle controller controls the instrument to give an engine fault text prompt;

[0041] the electronic control unit lights up the engine fault indicator light of the instrument to remind the driver to perform vehicle maintenance after ending the current driving cycle.

[0042] The engine fault handling method of the heavy hybrid power system as described above, preferably, in the case of a fourth level of engine fault, the driving performance restriction system is activated, and the power output of the engine or the electric motor is limited according to the torque, specifically comprising:

[0043] When the engine has a four-level fault, the corresponding fault code is retained in the electronic control unit;

[0044] The electronic control unit sends the fault level to the vehicle controller;

[0045] The vehicle controller determines whether the current driving mode is in series mode or parallel mode after receiving the four-level fault of the engine;

[0046] If it is in series mode, the engine continues to drive under this power, and the engine power output is limited according to the torque;

[0047] If it is in parallel mode, the power of the electric motor is dynamically limited to the corresponding torque state, and the power output of the electric motor is limited according to the torque;

[0048] The vehicle controller controls the instrument to give an engine fault text prompt;

[0049] The engine fault indicator light and the driver warning light of the instrument are lit by the electronic control unit to remind the driver that the vehicle has activated the driving performance limiting system, and the vehicle should be repaired after the current driving cycle is over.

[0050] The engine fault handling method of the heavy hybrid system as described above, preferably, in the case of a five-level engine fault, the driving performance limiting system is activated, and the power output of the engine or the electric motor is limited according to the vehicle speed, specifically comprising:

[0051] When the engine has a five-level fault, the corresponding fault code is retained in the electronic control unit;

[0052] The electronic control unit sends the fault level to the vehicle controller;

[0053] The vehicle controller limits the vehicle to 20km / h after receiving the five-level fault of the engine, and determines whether the current driving mode is in series mode or parallel mode;

[0054] If it is in series mode, the power output of the engine is limited according to the vehicle speed;

[0055] If it is in parallel mode, the power output of the electric motor is limited according to the vehicle speed, and the vehicle is forced to enter series mode, the engine induction system is used to make the vehicle reach the speed limit state, and the regulatory requirements are met;

[0056] The vehicle controller controls the instrument to give an engine fault text prompt;

[0057] The engine fault indicator light and the driver warning light of the instrument are lit by the electronic control unit to remind the driver that the vehicle has activated the driving performance limiting system, and the vehicle should be repaired after the current driving cycle is over.

[0058] The present application provides an engine fault handling method of a heavy hybrid system. When the engine system fault is encountered, the heavy hybrid system distinguishes the engine fault condition and corresponds to the regulation requirement, formulates the adjustment strategy of the heavy hybrid system according to the current state to handle the engine fault, protects the remaining power components from the damage caused by the engine fault, and meets the regulation limit of the heavy vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to make the objectives, technical solutions and advantages of the present application clearer, the following will further describe the present application with reference to the accompanying drawings, in which:

[0060] Figure 1 The flow chart of the engine fault handling method of the heavy hybrid system provided by the present application;

[0061] Figure 2 The engine fault handling strategy logic diagram when the engine fault level is level one;

[0062] Figure 3 The engine fault handling strategy logic diagram when the engine fault level is level two;

[0063] Figure 4 The engine fault handling strategy logic diagram when the engine fault level is level three;

[0064] Figure 5 The engine fault handling strategy logic diagram when the engine fault level is level four;

[0065] Figure 6 The engine fault handling strategy logic diagram when the engine fault level is level five. DETAILED DESCRIPTION

[0066] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses. The present disclosure can be implemented in numerous different forms, not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the present disclosure to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions and values set forth in these embodiments should be interpreted as merely exemplary, rather than as a limitation.

[0067] The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different parts. The terms "include", "comprise", and similar terms mean that the elements before the term encompass the elements listed after the term, and do not exclude the possibility of also encompassing other elements. "Up", "down", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0068] In the present disclosure, when it is described that a specific component is located between a first component and a second component, there can be an intervening component between the specific component and the first component or the second component, or there can be no intervening component. When it is described that a specific component is connected to other components, the specific component can be directly connected to the other components without an intervening component, or can not be directly connected to the other components with an intervening component.

[0069] All terms used in the present disclosure, including technical terms or scientific terms, have the same meanings as understood by a person of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary should be interpreted to have meanings consistent with their meanings in the context of relevant technology, and should not be interpreted in an idealized or excessively formalized sense, unless otherwise explicitly defined herein.

[0070] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification where appropriate.

[0071] The Heavy Duty Phase VI Emission Regulation requirements specify a Severe Functional Failure Monitoring, while adding the requirement for proper operation of the NOx control system and the driving performance limitation according to the failure of the corresponding system.

[0072] According to the corresponding system, if the reaction agent inventory is low, the reaction agent quality is abnormal, the reaction agent consumption is low, or there is a fault, the driving performance limitation system will be activated if it is not corrected in time. The vehicle should include two levels of driving performance limitation system, namely the primary driving performance limitation system (performance limitation) and the severe driving performance limitation system (effective limitation of vehicle operation).

[0073] The sixth stage emission regulation of heavy-duty vehicle makes basic provisions for functional failure and emission limit value, and clearly defines what kind of driver prompt or power limitation method should be used when the vehicle appears abnormal failure during operation. There is no problem in comprehensively applying this regulation to fuel vehicles, and the driving performance limitation and driver prompt of the whole vehicle can be realized through the engine electronic control unit, which can process the power adjustment of the vehicle under the failure of the engine and its emission; however, the power source of the hybrid vehicle is not only the engine, and when meeting the regulation, the safety of the power system switching and the limitation method of the driving performance of the whole vehicle need to be considered.

[0074] The hybrid system of heavy-duty vehicle lacks guiding regulations and standard constraints in terms of engine body and its emission failure, and the main machine factory needs to meet the following demand scenarios in terms of the hybrid architecture and power distribution of the vehicle system:

[0075] Meet the regulation limit, the hybrid power of heavy-duty vehicle needs to diagnose and start the driver warning system immediately when the engine and its emission system are abnormal, and according to the fault level, activate the induction system and other limiting measures to make the driver handle in time;

[0076] The treatment strategy should also be formulated according to the influence of engine failure on the vehicle and the driver, and the engine failure is divided into five levels, which are first level failure: no influence on engine operation and no influence on emission; second level failure: slight influence on engine operation and no influence on emission; third level failure: serious influence on engine operation; fourth level failure: emission leads to primary driving performance limitation; fifth level failure: emission leads to high level driving performance limitation. The treatment of the five levels needs to formulate strategies in combination with the influence of engine life and emission limitation;

[0077] At the same time, consider the actual output state of the rest of the hybrid system, evaluate the influence of engine operation abnormality on high pressure components, and then formulate the treatment measures of high pressure power components.

[0078] The present application provides an engine failure treatment scheme for a hybrid power system of a heavy-duty vehicle, which is a PHEV plug-in hybrid power assembly system. The PHEV contains two sets of power sources, namely engine and motor. In series working condition, the engine drives the heavy-duty vehicle to run; in parallel working condition, the engine and motor can independently drive the vehicle to run, and can work simultaneously or individually. The two modes realize flexible hybrid of engine driving, motor driving, range extending power generation and external charging.

[0079] The heavy-duty hybrid power system comprises an engine 1, which can be flexibly used for driving and range extending; an electric motor 2, which is used for driving the heavy-duty vehicle in pure electric or hybrid engine mode; an ECU 3, which is an engine electronic control unit, used for controlling engine operation, monitoring engine failure, and sending engine state information to a vehicle controller VCU 4; the VCU 4 is used for controlling the overall power output of the heavy-duty vehicle, switching the driving mode and power output source, protecting components, and reminding the driver; an instrument 5 is used for displaying prompt information to the driver 6, and the instrument 5 comprises an engine failure indicator 7 and a driver warning light 8 to prompt the driver 6 to repair as soon as possible.

[0080] As shown in the figure, the engine failure processing method of the heavy-duty hybrid power system provided by the embodiment specifically comprises the following steps in the actual execution process: Figure 1

[0081] Step S1, judging the failure level of the engine 1.

[0082] Step S2, if the engine failure level is level one, monitoring whether the power system can work normally through the response torque of the engine 1.

[0083] As shown in the figure, in one embodiment of the engine failure processing method of the heavy-duty hybrid power system, the step S2 specifically can comprise: Figure 2 Step S21, when the engine 1 occurs level one failure, storing the corresponding failure code in the electronic control unit (ECU) 3.

[0084] Step S22, sending the failure level to the vehicle controller (VCU) 4 through the electronic control unit (ECU) 3.

[0085] Step S23, after receiving the level one failure level of the engine 1, monitoring whether the power system can work normally through the response torque of the engine 1 by the vehicle controller (VCU) 4.

[0086] Step S24, if the power system can work normally, continuing to maintain the current power output state.

[0087] Step S25, lighting the engine failure indicator 7 of the instrument 5 through the electronic control unit (ECU) 3 to remind the driver 6 to repair the vehicle later.

[0088] Step S3, if the engine failure level is level two, judging the actual torque limiting level through the response torque of the engine 1, and switching the driving mode according to whether the actual limiting state can meet the demand of the driver.

[0089] As shown in the figure, in one embodiment of the engine failure processing method of the heavy-duty hybrid power system, the step S3 specifically can comprise:

[0090] Figure 3 ​​As shown, in one embodiment of the engine fault handling method of the heavy hybrid system of the present application, the step S3 can specifically include:

[0091] Step S31, when a secondary fault occurs in the engine 1, the corresponding fault code is retained in the electronic control unit (ECU) 3.

[0092] Step S32, the electronic control unit (ECU) 3 sends the fault level to the vehicle controller (VCU) 4.

[0093] Step S33, after receiving the secondary fault of the engine 1, the vehicle controller (VCU) 4 judges the actual torque limiting level through the response torque of the engine 1, and determines whether to maintain the current working condition according to the actual torque limiting level.

[0094] In one embodiment of the engine fault handling method of the heavy hybrid system of the present application, the step S33 can specifically include:

[0095] Step S331, confirm that the current driving mode is in series working condition or parallel working condition.

[0096] Step S332, if it is series working condition, the vehicle controller (VCU) 4 obtains the driving demand of the driver 6.

[0097] Step S333, the vehicle controller (VCU) 4 judges whether the maximum torque of the actual limiting state meets the driving demand.

[0098] Step S334, if it meets, continue to maintain the current working condition.

[0099] Step S335, if it does not meet, judge whether the motor and the battery power meet the parallel working condition.

[0100] Step S336, if it meets, enter the motor drive, and the vehicle controller (VCU) 4 controls the instrument 5 to remind the driver 6 to switch the driving mode through words.

[0101] After entering the motor drive, enter the parallel working condition, at this time, use the motor 2 as the main driving state, and then use the engine 1 in parallel to generate electricity.

[0102] Step S337, if it does not meet, continue to maintain the current working condition.

[0103] If one of the motor and the battery power does not meet the parallel working condition, return to the series mode again, and use the engine as the main drive.

[0104] Step S34, the vehicle controller (VCU) 4 controls the instrument 5 to give an engine fault word prompt.

[0105] Step S35, the engine fault indicator light 7 of the instrument 5 is lit by the electronic control unit (ECU) 3 to remind the driver 6 to carry out vehicle maintenance after ending the current driving cycle.

[0106] Step S4, if the engine fault level is level three, the driving mode is forcibly switched to pure electric driving, and the engine operation is stopped.

[0107] As shown in the engine fault handling method of the heavy hybrid system of the present application, in one embodiment, the step S4 can specifically include: Figure 4

[0108] Step S41, when the engine has a level three fault, the corresponding fault code is retained in the electronic control unit (ECU) 3.

[0109] Step S42, the electronic control unit (ECU) 3 sends the fault level to the vehicle controller (VCU) 4.

[0110] Step S43, after receiving the level three fault of the engine 1, the vehicle controller (VCU) 4 obtains the driving demand of the driver 6.

[0111] Step S44, the vehicle controller (VCU) 4 judges whether the current power and the motor state meet the parallel working condition.

[0112] Step S45, if it is met, the driving mode is forcibly switched to pure electric driving, and the engine operation is stopped.

[0113] Further, if the battery power or the motor 2 state cannot support the vehicle to run for a long time, the minimum driving state is ensured and the driver 6 is prompted to drive into the service station for maintenance as soon as possible.

[0114] Step S46, if it is not met, the vehicle operation is stopped.

[0115] Step S47, the vehicle controller (VCU) 4 controls the instrument 5 to give an engine fault text prompt.

[0116] The engine fault text prompt through the instrument 5 can remind the driver to drive into the service station for maintenance as soon as possible.

[0117] Step S48, the engine fault indicator light 7 of the instrument 5 is lit by the electronic control unit (ECU) 3 to remind the driver 6 to carry out vehicle maintenance after ending the current driving cycle.

[0118] Step S5, if the engine fault level is level four, the driving performance limiting system is activated, and the power output of the engine 1 or the motor 2 is limited according to the torque.

[0119] As shown in the engine fault handling method of the heavy hybrid system of the present application, in one embodiment, the step S4 can specifically include: Figure 5 ​As shown, in one embodiment of the method for handling engine failure of a heavy-duty hybrid system of the present invention, step S5 may specifically include:

[0120] Step S51: When a level 4 fault occurs in the engine, the corresponding fault code is stored in the electronic control unit (ECU) 3.

[0121] In step S52 , the electronic control unit (ECU) 3 sends the fault level to the vehicle control unit (VCU) 4 .

[0122] Step S53 : After receiving the fourth-level fault of the engine 1 , the vehicle controller (VCU) 4 determines whether the current driving mode is the series mode or the parallel mode.

[0123] Step S54: If the vehicle is in the series mode, the engine 1 is continued to be used for driving under this power, and the power output of the engine 1 is limited according to the torque.

[0124] Step S55: If in the parallel mode, the power of the motor 2 is dynamically limited to the corresponding torque state, and the power output of the motor 2 is limited according to the torque.

[0125] Level 4 faults affect emission regulations. According to regulatory restrictions, power will be limited to less than 75% output. The vehicle controller (VCU) 4 determines whether it is currently in series or parallel mode. If it is in the series state, engine 1 continues to be used for driving under this power. If it is in the parallel mode, the power of motor 2 is dynamically limited to the corresponding torque state to meet regulatory requirements.

[0126] Step S56: The vehicle controller (VCU) 4 controls the instrument panel 5 to issue a text prompt indicating an engine failure.

[0127] Step S57 : The electronic control unit (ECU) 3 lights up the engine fault indicator light 7 and the driver warning light 8 of the instrument panel 5 to remind the driver 6 that the drivability restriction system has been activated and to perform vehicle maintenance after the current driving cycle ends.

[0128] Step S6: If the engine fault level is level five, the drivability limitation system is activated and the power output of the engine 1 or the motor 2 is limited according to the vehicle speed.

[0129] like Figure 6 As shown, in one embodiment of the method for handling engine failure of a heavy-duty hybrid system of the present invention, step S6 may specifically include:

[0130] Step S61 : When a level 5 fault occurs in the engine 1 , the corresponding fault code is stored in the electronic control unit (ECU) 3 .

[0131] Step S62, the electronic control unit (ECU) 3 sends the fault level to the vehicle control unit (VCU) 4.

[0132] Step S63, after receiving the five-level fault of the engine 1, the vehicle control unit (VCU) 4 limits the vehicle to 20km / h and judges whether the current driving mode is in series mode or parallel mode.

[0133] Step S64, if in series mode, limit the power output of the engine 1 according to the vehicle speed.

[0134] Step S65, if in parallel mode, forcibly enter series mode by limiting the power output of the motor 2 according to the vehicle speed, use the engine induction system to make the vehicle reach the speed limit state, and meet the regulatory requirements.

[0135] The five-level fault affects the emission regulations, and according to the regulatory restrictions, the vehicle is limited to 20km / h, and the vehicle control unit (VCU) 4 will forcibly enter the series mode, use the engine induction system to make the vehicle reach the speed limit state, and meet the regulatory requirements.

[0136] Step S66, the vehicle control unit (VCU) 4 controls the instrument 5 to give an engine fault text prompt.

[0137] Step S67, the electronic control unit (ECU) 3 lights up the engine fault indicator 7 and the driver warning light 8 of the instrument 5 to remind the driver that the current vehicle has activated the driving performance limiting system, and to perform vehicle maintenance after the current driving cycle is completed.

[0138] When the heavy vehicle uses a hybrid power system, the present application covers the system currently limited by the emission regulations, and due to the particularity of the hybrid power system, a more optimal strategy is developed to realize smooth power switching and driver warning system prompt.

[0139] The engine fault handling method of the heavy hybrid power system provided by the embodiment of the present application, when the heavy hybrid power system encounters an engine system fault, by distinguishing the engine fault condition and corresponding to the regulatory requirements, a strategy is developed that can handle the engine fault according to the current state of the heavy hybrid power system, while protecting the remaining power components from damage caused by the engine fault, and can also meet the regulatory restrictions of heavy vehicles.

[0140] So far, the embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

[0141] Although some specific embodiments of the present disclosure have been described in detail by way of example with reference to the drawings, it is to be understood that the above examples are intended to be illustrative only and are not intended to limit the scope of the present disclosure. It is to be understood that modifications or equivalent arrangements of the above embodiments can be made by those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A method for handling engine failure in a heavy-duty hybrid system, characterized in that: include: Determine the engine fault level. Engine faults are divided into five levels, namely, level 1 fault: does not affect engine operation and does not affect emissions; Level 2 fault: slightly affects engine operation and does not affect emissions; Level 3 fault: seriously affects engine operation; Level 4 fault: emissions lead to primary driving performance restrictions; Level 5 Fault: Emissions causing advanced driving performance limitations; If the engine fault level is level one, the engine response torque is used to monitor whether the power system can operate normally; If the engine fault level is level 2, the actual torque limit level is determined by the engine's response torque, and the driving mode is switched based on whether the actual limit level can meet the driver's needs; If the engine fault level is level three, the driving mode will be forced to switch to pure electric driving and the engine will be stopped; If the engine fault level is level four, the driving performance limitation system is activated and the power output of the engine or electric motor is limited according to the torque; If the engine fault level is level five, the driving performance limitation system will be activated and the power output of the engine or motor will be limited according to the vehicle speed. When the engine fault level is level three, the driving mode is forcibly switched to pure electric driving and the engine is stopped, specifically including: When a third-level fault occurs in the engine, the corresponding fault code will be retained in the electronic control unit; The electronic control unit sends the fault level to the vehicle controller; After receiving the third-level engine fault, the vehicle controller obtains the driver's driving requirements; The vehicle controller determines whether the current power and motor status meet the parallel working conditions; If the conditions are met, the driving mode will be forced to switch to pure electric driving and the engine will be stopped; If not satisfied, the vehicle will be stopped; The vehicle controller controls the instrument to give text prompts for engine failures; The electronic control unit illuminates the engine fault indicator light on the instrument to remind the driver to perform vehicle maintenance after the current driving cycle.

2. The engine failure handling method of a heavy-duty hybrid system according to claim 1, characterized in that: When the engine fault level is level one, monitoring whether the power system can operate normally through the engine response torque specifically includes: When a primary fault occurs in the engine, the corresponding fault code will be stored in the electronic control unit; Send the fault level to the vehicle controller through the electronic control unit; After receiving the engine's first-level fault level, the vehicle controller monitors whether the power system can operate normally through the engine's response torque; If the power system can work normally, the current power output state will continue to be maintained; The electronic control unit lights up the engine fault indicator light on the instrument to remind the driver to perform vehicle maintenance later.

3. The engine failure handling method of a heavy-duty hybrid system according to claim 1, characterized in that: When the engine fault level is level 2, the actual torque limit level is determined by the engine's response torque, and the driving mode is switched based on whether the actual limit state can meet the driver's needs. Specifically, the following steps are performed: When a secondary fault occurs in the engine, the corresponding fault code will be retained in the electronic control unit; The electronic control unit sends the fault level to the vehicle controller; After receiving the secondary fault of the engine, the vehicle controller determines the actual torque limit level through the engine's response torque and determines whether to maintain the current operating condition based on the actual torque limit level; The vehicle controller controls the instrument to give text prompts for engine failures; The electronic control unit illuminates the engine fault indicator light on the instrument to remind the driver to perform vehicle maintenance after the current driving cycle.

4. The engine failure handling method of a heavy-duty hybrid system according to claim 3, characterized in that: After receiving the secondary fault of the engine, the vehicle controller determines the actual torque limit level through the response torque of the engine, and determines whether to maintain the current operating condition according to the actual torque limit level, specifically including: Confirm that the current driving mode is in series or parallel mode; If it is a series working condition, the vehicle controller obtains the driver's driving needs; The vehicle controller determines whether the maximum torque in the actual limiting state meets the driving requirements; If satisfied, continue to maintain the current working condition; If not, determine whether the electric motor and battery power meet the parallel working condition; If the conditions are met, the system will enter motor drive mode, and the vehicle controller will control the instrument panel to remind the driver to switch driving modes through text. If not satisfied, continue to maintain the current working condition.

5. The engine failure handling method of a heavy-duty hybrid system according to claim 1, characterized in that: When the engine fault level is level 4, the drivability limitation system is activated and the power output of the engine or motor is limited according to the torque, specifically including: When a level 4 fault occurs in the engine, the corresponding fault code will be retained in the electronic control unit; The electronic control unit sends the fault level to the vehicle controller; After receiving the engine's level 4 fault, the vehicle controller determines whether the current driving mode is in series mode or parallel mode; If in series mode, the engine will continue to be used for driving under this power and the power output of the engine will be limited according to the torque; If in parallel mode, the power of the motor is dynamically limited to the corresponding torque state, and the power output of the motor is limited according to the torque; The vehicle controller controls the instrument to give text prompts for engine failures; The electronic control unit lights up the engine fault indicator light and driver warning light on the instrument panel to remind the driver that the driving performance restriction system has been activated and the driver should repair the vehicle after completing the current driving cycle.

6. The engine failure handling method of a heavy-duty hybrid system according to claim 1, characterized in that: When the engine fault level is level five, the drivability limitation system is activated and the power output of the engine or motor is limited according to the vehicle speed, specifically including: When a level 5 fault occurs in the engine, the corresponding fault code will be retained in the electronic control unit; The electronic control unit sends the fault level to the vehicle controller; After receiving the engine's level 5 fault, the vehicle controller limits the vehicle to 20 km / h and determines whether the current driving mode is series mode or parallel mode; If in series mode, the engine's power output is limited according to vehicle speed; If in parallel mode, the motor's power output is forced into series mode based on the vehicle speed limit, using the engine induction system to bring the vehicle to the speed limit to meet regulatory requirements. The vehicle controller controls the instrument to give text prompts for engine failures; The electronic control unit lights up the engine fault indicator light and driver warning light on the instrument panel to remind the driver that the driving performance restriction system has been activated and the driver should repair the vehicle after completing the current driving cycle.

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