Dew-point-free front oxygen sensor heating and engine starting control method and system and vehicle

Abstract

The invention discloses a dew-point-free front oxygen sensor heating and engine starting control method and system and a vehicle, and the method comprises the steps that if an engine starting mode is starting forbidding or the vehicle runs in a pure electric mode, a dew-point-free front oxygen sensor is controlled not to be heated, and an engine is controlled not to be started; if the engine starting mode is high-priority starting, controlling the heating of the oxygen sensor before dew point and the starting of the engine to be carried out at the same time; if the engine starting mode is middle priority starting, firstly controlling the dew-point-free front oxygen sensor to be heated to k * T, and then controlling the engine to be started; and if the engine starting mode is low-priority starting, the non-dew-point front oxygen sensor is controlled to be heated to T, and then the engine is controlled to be started. By the adoption of the method, the problem of emission deterioration caused by frequent starting and stopping of an engine of the hybrid electric vehicle can be solved, and meanwhile the problem that the service life is shortened due to unnecessary heating of the dew-point-free front oxygen sensor is solved.

Description

Technical Field

[0001] This invention belongs to the field of engine control in hybrid electric vehicles, specifically relating to a method, system, and vehicle for controlling the heating of an oxygen sensor before dew point and engine start-up. Background Technology

[0002] An oxygen sensor is a sensor that monitors the oxygen content in the exhaust gas of a hybrid electric vehicle engine. The system uses the oxygen sensor to detect the oxygen content in the exhaust gas to calculate the real-time air-fuel ratio in the engine cylinder, thereby achieving precise control of the air-fuel mixture to minimize exhaust emissions.

[0003] The pre-oxygen sensor is installed upstream of the exhaust system (before the three-way catalytic converter). Its normal operation requires the internal sensing element to reach a certain temperature, typically between 650°C and 800°C. Therefore, the pre-oxygen sensor is usually equipped with a heating circuit to actively heat the sensing element and maintain it at the appropriate operating temperature. On the other hand, the pre-oxygen sensor operates in the exhaust system, where condensation is prone to occur. If the high-temperature sensing element encounters condensation, it can cause the sensing element to rupture, resulting in damage to the pre-oxygen sensor. Therefore, before confirming that there is no condensation around the pre-oxygen sensor (i.e., before the exhaust system wall temperature exceeds the dew point temperature), the pre-oxygen sensor can only be heated at low power for protection. Only after confirming that the wall temperature exceeds the dew point temperature can the pre-oxygen sensor begin full-power heating to quickly reach the operating temperature, thereby achieving closed-loop control of the air-fuel ratio.

[0004] In summary, the heating process of the front oxygen sensor from the start of heating until it reaches its normal operating temperature involves two stages: The first is protective heating before the dew point, which occurs after the engine starts. During this stage, the sensor is primarily heated by engine exhaust gases, and the duration varies depending on the ambient temperature, generally ranging from 10 to 120 seconds; the lower the ambient temperature, the longer the heating time. The second stage is full-power heating after the dew point, which relies mainly on the front oxygen sensor's own heating circuit. The heating time varies depending on the specific front oxygen sensor, generally ranging from 5 to 7 seconds. During both stages, the front oxygen sensor cannot function normally, and the air-fuel mixture control is in an open-loop state. This typically occurs for a period after the engine has undergone a prolonged shutdown and restart, and is also the stage with the worst exhaust emissions.

[0005] Hybrid electric vehicles often experience frequent start-stop cycles during driving, and these starts are often accompanied by high-power engine output. If the front oxygen sensor malfunctions during this time, it can lead to the emission of large amounts of pollutants. Therefore, an increasing number of hybrid electric vehicles are equipped with dew-point-free front oxygen sensors (i.e., front oxygen sensors that can quickly reach their operating temperature at high power without undergoing a protective heating phase). These sensors significantly reduce the open-loop control time of the air-fuel mixture, thereby lowering exhaust pollutant emissions.

[0006] For hybrid electric vehicles equipped with dew-point-free pre-oxygen sensors, there are currently two main heating strategies: The first is to activate the pre-oxygen sensor heating when the vehicle is drivable (i.e., the ready light is on), regardless of whether the engine is running. This ensures that the air-fuel mixture can achieve closed-loop control immediately with each engine start during the driving cycle, but it affects the lifespan of the pre-oxygen sensor. The second strategy is to activate the pre-oxygen sensor heating simultaneously with engine start. This can extend the lifespan of the pre-oxygen sensor, but there will still be a period of open-loop control (5-7 seconds) between engine start and the pre-oxygen sensor reaching its operating temperature, which is detrimental to exhaust emissions. Summary of the Invention

[0007] The purpose of this invention is to provide a method, system, and vehicle for heating a dew-point pre-oxygen sensor and controlling engine start-up, in order to optimize the emission deterioration problem caused by frequent engine start-stop in hybrid vehicles, while avoiding the shortened lifespan problem caused by unnecessary heating of the dew-point pre-oxygen sensor.

[0008] In a first aspect, the present invention provides a method for heating an oxygen sensor before dew point and controlling engine start-up, comprising: If the engine start mode is set to "start prohibited" or the vehicle is running in pure electric mode, the oxygen sensor before the dew point sensor is not heated, and the engine does not start.

[0009] If the engine start mode is high priority start, the oxygen sensor heating before dew point is controlled to proceed simultaneously with engine start.

[0010] If the engine start mode is medium priority start, the oxygen sensor before dew point is heated to k*T first, and then the engine is started.

[0011] If the engine start mode is low priority start, the oxygen sensor before dew point is heated to T first, and then the engine is started.

[0012] Where T represents the preset operating temperature of the oxygen sensor before dew point, and k represents the preset percentage coefficient, 0 < k < 1.

[0013] Preferably, the preset proportion coefficient k = 0.7. First, the oxygen sensor before the dew point is heated to 0.7T, which takes about 3 to 4 seconds, and then the engine is started. This shortens the open-loop control time of the air-fuel mixture and ensures timely engine start, achieving a balance between the heating control of the oxygen sensor before the dew point and the engine start control.

[0014] Preferably, if any one of conditions 1a to 1g is met, the engine starting mode is determined to be prohibited from starting. Among them, condition 1a is: the fuel level sensor is fault-free, the remaining fuel level in the fuel tank is less than or equal to the first preset fuel level threshold, and there is an engine torque output fault; condition 1b is: there is a phase sensor fault or a generator fault; condition 1c is: a request to prevent engine starting is received for a speed sensor fault diagnosis; condition 1d is: within the current key cycle (i.e., the power position is switched from OFF to ON or from ON to OFF), the number of consecutive engine start failures is greater than or equal to a preset number threshold; condition 1e is: the vehicle ready light is not lit (i.e., the vehicle status is non-drivable mode), the remaining fuel level in the fuel tank is greater than the second preset fuel level threshold, the front air volume adjustment signal is not OFF, no remote air conditioning start request or remote front defrost start request is received, no AC gun discharge enable signal is received, no camping mode start signal is received, and no DC discharge gun connection signal is received; condition 1f is: a fuel tank cap unlock request is received, and the vehicle speed is less than the first preset vehicle speed threshold; condition 1g is: the driving mode is forced EV mode.

[0015] Conditions 1a (normal fuel level sensor + low fuel level + torque output fault), 1b (phase sensor / generator fault), and 1c (speed sensor fault diagnosis request) directly pinpoint critical components that affect engine operation. For example, the phase sensor monitors crankshaft / camshaft phase; if it malfunctions, engine ignition timing will be incorrect, and forced starting may result in pistons hitting valves and power interruption. Starting the engine when the generator is faulty will cause the electronic control system to malfunction due to lack of power. These three conditions effectively prevent such hardware damage at its source.

[0016] Condition 1d (continuous starting failures exceeding the threshold within the current key cycle) is essentially to prevent overloading of the starting system. Engine starting relies on the starter motor; multiple consecutive starting failures (such as a depleted battery or starter jamming due to fuel injector malfunction) will cause the starter motor to operate under high load for an extended period, potentially burning out the coil. Condition 1d, by limiting the number of attempts, forcibly interrupts invalid starting attempts, protecting the starter motor and battery.

[0017] Condition 1e (ready light off + high fuel level + no remote air conditioning / defrosting / discharging / camping signal) is primarily used to distinguish between drivable and indestructible states. The ready light indicates that the vehicle's electronic control and power systems are ready. Generally, the engine can only be started after the ready light is on. However, in some special cases, such as remote air conditioning, external / DC discharging, or camping mode, starting the engine is permitted without the ready light being on. Condition 1e excludes these special cases that allow engine starting, preventing misjudgments.

[0018] Condition 1f (fuel tank cap unlock request + low vehicle speed) and condition 1g (forced EV mode) precisely match the vehicle's operating logic. When the fuel tank cap is unlocked (usually in a parking refueling scenario), allowing the engine to start could lead to fuel vapor leakage due to the open fuel system cap, posing a safety risk. Forced EV mode is a pure electric driving command for hybrid vehicles, which prohibits engine start, providing a precise response to the user's driving intentions and avoiding power mode conflicts.

[0019] Preferably, if condition 2a is met, the engine start mode is determined to be high-priority start. Condition 2a is: the driver has a strong acceleration need and needs to activate the range extender.

[0020] The requirement to activate the range extender serves as a rational filter for strong acceleration demands. If the driver has a strong acceleration need, but the battery currently has sufficient remaining charge and its discharge power is fully capable of meeting the high-power output of the electric motor, then activating the range extender is unnecessary. In range-extended electric vehicles, engine starting demands may arise from multiple scenarios. For example, battery SOC falling below a threshold (regular charging start), remote air conditioning activation (idle power supply start), and strong acceleration. Different scenarios have different urgency requirements for engine starting. If strong acceleration demands are delayed by the regular starting logic, it will directly affect the driving experience and even pose safety risks (such as insufficient power when overtaking). By prioritizing the driver's strong acceleration demand and the need to activate the range extender, the range extender can respond at the fastest speed, ensuring the power reliability of core driving scenarios.

[0021] Preferably, if the accelerator pedal opening is greater than a preset opening threshold and continues for a preset time, it indicates that the driver has a strong acceleration demand; if the original driving power demanded by the driver is greater than the difference between the available driving power and a preset power offset, it indicates that the range extender needs to be activated.

[0022] Preferably, if condition 3a or 3b is met, the engine start mode is determined to be medium priority start. Condition 3a is: receiving a parking charging request via vehicle-to-everything (V2X) interaction; condition 3b is: receiving an air conditioning cooling or heating request, and the current battery power is insufficient to meet the air conditioning cooling or heating request.

[0023] The parking charging request input via the vehicle-to-everything (V2X) interface corresponds to a user-initiated charging scenario (e.g., when the vehicle is parked, the user triggers the engine to generate electricity via the V2X interface). In this case, starting the engine allows it to act as a temporary generator to replenish the battery. If the current battery power is insufficient to meet the air conditioning's cooling or heating requirements, the focus is on matching comfort needs with battery capacity. Air conditioning is a core comfort feature of the vehicle, but cooling requires significant power. If the battery's remaining charge is low and its discharge power is insufficient, relying solely on battery power will result in the air conditioning's vent temperature not meeting standards, and may even affect subsequent driving range due to excessive power consumption. In this case, starting the engine generates electricity to power the air conditioning, ensuring a comfortable temperature inside the vehicle. Conditions 3a and 3b serve parking charging and comfort; their engine start priority is slightly lower than condition 2a, which serves driving safety and power response, so they are classified as medium-priority start conditions.

[0024] Preferably, if any one of conditions 4a to 4c is met, the engine start mode is determined to be low-priority start. Condition 4a is: the current actual SOC is less than the difference between the preset target maintenance SOC and the preset SOC offset; condition 4b is: the vehicle is not in forced EV mode, the current actual SOC is less than the preset target maintenance SOC, and the vehicle speed is greater than the second preset vehicle speed threshold; condition 4c is: a winter mode activation signal is received, and the vehicle speed is greater than the third preset vehicle speed threshold.

[0025] Condition 4a focuses on triggering engine start when the SOC is low, using engine power to replenish the battery. Condition 4b focuses on the dynamic balance of SOC during driving. On one hand, the non-mandatory EV mode excludes the user's explicit intention to drive purely on electric power, avoiding conflict with user needs; on the other hand, a vehicle speed greater than the second preset speed threshold ensures that the engine operates in an efficient range when starting, achieving both SOC recovery and power generation efficiency. Both conditions 4a and 4b are based on battery SOC constraints, using engine start to generate electricity and maintain the battery SOC within a reasonable range, avoiding the impact of low battery on subsequent use, while also avoiding ineffective start-ups when the battery is high. Condition 4c aims to improve system performance in winter conditions by starting the engine, avoiding functional limitations caused by battery degradation at low temperatures. Although conditions 4a to 4c all involve engine start, they belong to low-priority scenarios. For example, a SOC slightly below the buffer line or driving at medium to high speeds in winter will not directly affect driving safety or current comfort; therefore, engine start-ups triggered by conditions 4a, 4b, or 4c are classified as low-priority start-up conditions.

[0026] Preferably, the third preset vehicle speed threshold is less than the second preset vehicle speed threshold.

[0027] In a second aspect, the present invention provides a dew-point pre-oxygen sensor heating and engine start control system, including a controller configured to execute the above-described dew-point pre-oxygen sensor heating and engine start control method.

[0028] Thirdly, the present invention provides a vehicle including the aforementioned dew-point-free pre-oxygen sensor heating and engine start control system.

[0029] This invention combines the pre-dew-point oxygen sensor heating strategy with the engine start-up strategy. Specifically, it determines the heating timing of the pre-dew-point oxygen sensor based on the expected engine start-up, and then determines the engine start-up time based on the heating status of the pre-dew-point oxygen sensor. This effectively resolves the contradiction of "overheating" or "underheating" of the pre-dew-point oxygen sensor, significantly optimizing the emission degradation problem caused by frequent start-stop in hybrid vehicles, while also avoiding the shortened lifespan problem caused by unnecessary heating of the pre-dew-point oxygen sensor. Detailed analysis follows: (1) For scenarios where the engine is prohibited from starting or the vehicle is operating purely on electric power, there is no expectation of starting, the oxygen sensor before the dew point is not heated, and the engine is not started. This reduces energy consumption and avoids shortening the lifespan of the oxygen sensor before the dew point, thus balancing energy consumption control and hardware protection. The core function of the oxygen sensor before the dew point is to detect the oxygen concentration in the engine exhaust to provide a basis for fuel injection quantity adjustment. The oxygen sensor before the dew point is only meaningful when the engine is started and exhaust is being produced. If the engine has been determined to be prohibited from starting or the vehicle is operating purely on electric power (without engine exhaust), heating the oxygen sensor before the dew point is completely useless and will instead consume onboard power. At the same time, the oxygen sensor before the dew point is in a state of heating without exhaust detection requirements for a long time, which will lead to unnecessary wear and tear on the heating element and shorten its service life.

[0030] (2) For high-priority starts, the engine has a high starting demand and its priority is higher than the pre-dew point oxygen sensor heating. Therefore, the pre-dew point oxygen sensor heating and engine start are carried out simultaneously, and there is no delay in engine start.

[0031] (3) For medium-priority starts, the engine start requirement is relatively high, and its priority is comparable to that of heating the pre-dew point oxygen sensor. Therefore, the pre-dew point oxygen sensor is heated to k*T before the engine is started. The core of this strategy is to find the optimal solution between engine start efficiency and pre-dew point oxygen sensor pre-processing. Although the requirement for medium-priority starts is not as urgent as that for high-priority starts, it is still necessary to avoid excessive waiting time. The k*T design achieves the pre-processing effect, and the pre-dew point oxygen sensor does not need to be heated to the full working temperature. It only needs to reach a semi-ready state, which can shorten the subsequent mixture control open-loop time. After the engine starts, the pre-dew point oxygen sensor can be heated from k*T to T in a short time and start working. This avoids the problem of the pre-dew point oxygen sensor taking effect too slowly during synchronous starts and saves waiting time compared to heating to T before starting.

[0032] (4) For low-priority starts, where engine start-up demand is low and its priority is lower than the heating of the oxygen sensor before dew point. Therefore, the oxygen sensor before dew point is heated to T before the engine is started. The core of this strategy is to maximize the accuracy of emission control by delaying engine start-up, adapting to the needs of low-urgency scenarios. The design of heating the oxygen sensor before dew point to T before starting the engine ensures that the oxygen sensor before dew point is fully ready at the moment of engine start-up. From the moment exhaust is generated, the oxygen sensor before dew point can accurately detect the oxygen concentration, directly providing accurate data to the fuel injection system and avoiding excessive emissions during the transition period caused by the oxygen sensor before dew point is not ready in the early stage of engine start-up. Attached Figure Description

[0033] Figure 1 This is a flowchart of the method for heating the oxygen sensor before dew point and controlling the engine start-up in an embodiment of the present invention. Detailed Implementation

[0034] To gain a more detailed understanding of the features and technical content of the embodiments of the present invention, the implementation of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to limit the invention.

[0036] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0037] like Figure 1 As shown, the method for controlling oxygen sensor heating and engine start-up without dew point in this embodiment of the invention includes the following steps: S1. Determine if the engine start mode is disabled. If yes, execute S12; otherwise, execute S2.

[0038] In some embodiments, if any one of conditions 1a to 1g is met, the engine starting mode is determined to be prohibited from starting. Condition 1a is: the fuel level sensor is fault-free, the remaining fuel level in the fuel tank is less than or equal to a first preset fuel level threshold, and there is an engine torque output fault. Condition 1b is: there is a phase sensor fault or a generator fault. Condition 1c is: a request to prohibit engine starting is received for a speed sensor fault diagnosis. Condition 1d is: within the current key cycle (power switch from OFF to ON or from ON to OFF), the number of consecutive engine starting failures is greater than or equal to a preset threshold. Condition 1e is: the vehicle ready light is not illuminated (i.e., the vehicle status is in non-drivable mode), the remaining fuel level in the fuel tank is greater than a second preset fuel level threshold, the front airflow adjustment signal is not OFF, no remote air conditioning activation request or remote front defrost activation request is received, no AC gun discharge enable signal is received, no camping mode activation signal is received, and no DC discharge gun connection signal is received. Condition 1f is: a fuel tank cap unlock request is received, and the vehicle speed is less than a first preset vehicle speed threshold. Condition 1g is: Driving mode is forced EV mode.

[0039] As an example, the first preset fuel level threshold is 5L, the preset number of times threshold is 3, the second preset fuel level threshold is 8L, and the first preset vehicle speed threshold is 2km / h.

[0040] Normally, the engine can only be started after the "ready" light illuminates. However, in some special cases, such as remote air conditioning activation, external / DC discharge, or camping mode, the engine can be started without the "ready" light being on. Therefore, if there are no other engine start-prohibition signals and the vehicle's "ready" light is not illuminated, and the remaining fuel level in the tank is greater than the second preset fuel level threshold, the engine can be started if the front airflow control signal is not OFF, a remote air conditioning activation request or a remote front defrost activation request is received, an AC discharge enable signal is received, a camping mode activation signal is received, or a DC discharge gun connection signal is received. In this case, the engine start-prohibition indicator will be reset to 0.

[0041] S2. Determine if the engine start mode is high priority start. If yes, execute S3; otherwise, execute S4.

[0042] In some embodiments, if condition 2a is met, the engine start mode is determined to be high-priority start. Condition 2a is: the driver has a strong acceleration need and needs to activate the range extender.

[0043] In some embodiments, if the accelerator pedal opening degree is greater than a preset opening threshold and remains so for a preset time, it indicates that the driver has a strong acceleration demand; if the driver's original demand for drive power is greater than the difference between the available drive power and a preset power offset, it indicates that the range extender needs to be activated. For example, the preset opening threshold is 80%, and the preset time is 2 seconds. The preset power offset is related to the accelerator pedal opening degree and the battery's maximum allowable discharge power, and is obtained through calibration.

[0044] S3. Control the oxygen sensor heating before dew point to start simultaneously with engine start, and then stop.

[0045] S4. Determine if the engine start mode is medium priority start. If yes, execute S5; otherwise, execute S7.

[0046] In some embodiments, if condition 3a or 3b is met, the engine start mode is determined to be medium-priority start. Condition 3a is: a parking charging request is received via vehicle-to-everything (V2X) interaction. Condition 3b is: an air conditioning cooling or heating request is received, and the current battery power is insufficient to meet the air conditioning cooling or heating request.

[0047] S5. Control the oxygen sensor to heat before dew point, then execute S6.

[0048] S6. Determine if the temperature of the oxygen sensor before dew point reaches k*T. If yes, proceed to S10; otherwise, continue with S6. Here, T represents the preset operating temperature of the oxygen sensor before dew point, and k represents the preset percentage coefficient, where 0 < k < 1.

[0049] In some embodiments, the preset proportion coefficient k = 0.7.

[0050] S7. Determine if the engine start mode is low priority start. If yes, execute S8; otherwise, execute S11.

[0051] In some embodiments, if any one of conditions 4a to 4c is met, the engine start mode is determined to be low-priority start. Condition 4a is: the current actual SOC is less than the difference between a preset target maintained SOC and a preset SOC offset. Condition 4b is: the vehicle is not in forced EV mode, the current actual SOC is less than the preset target maintained SOC, and the vehicle speed is greater than a second preset vehicle speed threshold. Condition 4c is: a winter mode activation signal is received, and the vehicle speed is greater than a third preset vehicle speed threshold.

[0052] In some embodiments, the third preset vehicle speed threshold is less than the second preset vehicle speed threshold. For example, the second preset vehicle speed threshold is 36 km / h, and the third preset vehicle speed threshold is 10 km / h.

[0053] S8. Control the oxygen sensor to heat before dew point, and then execute S9.

[0054] S9. Determine whether the temperature of the oxygen sensor before the dew point reaches T. If yes, execute S10; otherwise, continue executing S9.

[0055] S10, control the engine to start, then stop.

[0056] S11. Determine that the vehicle is operating in pure electric mode, and then execute S12.

[0057] S12, control the oxygen sensor before dew point to not heat up, the engine to not start, and then return to execute S1.

[0058] Under high-priority start-up, the oxygen sensor heating before dew point starts simultaneously with engine start-up. After engine start-up, there will be an open-loop time (5s~7s) for the air-fuel mixture control, but this cannot be avoided for driving safety and power response.

[0059] Under medium-priority start-up, the oxygen sensor before dew point is heated to 0.7T before the engine starts. There is a 3-4 second delay in engine start-up, and the air-fuel mixture control still has a 2-3 second open-loop time after engine start-up. However, overall, this is shorter than the 5-7 second open-loop time. Since medium-priority operation prioritizes parking refueling and comfort, the slight 3-4 second delay in engine start-up has a very small impact on comfort.

[0060] Under low-priority start-up, the oxygen sensor before the dew point is heated to T before the engine starts. There will be a delay of 5 to 7 seconds before the engine starts, but the air-fuel mixture control will enter closed-loop control immediately after the engine starts. Since low priority does not directly affect driving safety or current comfort, a delay of 5 to 7 seconds before engine starts is acceptable.

[0061] If two, three, or four engine start-up mode conditions are met simultaneously, the control logic is executed in the following order of priority: Inhibit Start (IPU) > High Priority Start (HPU) > Medium Priority Start (MPU) > Low Priority Start (LPU), that is, IPU takes precedence over HPU, HPU takes precedence over MPU, and MPU takes precedence over LPU.

[0062] In addition, embodiments of the present invention also provide a dew-free pre-oxygen sensor heating and engine start control system, which includes a controller configured to execute the above-described dew-free pre-oxygen sensor heating and engine start control method.

[0063] In addition, embodiments of the present invention also provide a vehicle (such as a PHEV, REEV, HEV, or other hybrid electric vehicle) that includes the aforementioned dew-point-free pre-oxygen sensor heating and engine start control system.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the heating of an oxygen sensor before dew point and for controlling engine start-up, characterized in that, include: If the engine start mode is set to prohibit start or the vehicle is running in pure electric mode, the oxygen sensor before the dew point will not be heated, and the engine will not start. If the engine start mode is high priority start, then the heating of the oxygen sensor before dew point is controlled to proceed simultaneously with the engine start. If the engine start mode is medium priority start, the oxygen sensor before the dew point is heated to k*T first, and then the engine is started. If the engine start mode is low priority start, the oxygen sensor before the dew point is heated to T first, and then the engine is started. Where T represents the preset operating temperature of the oxygen sensor before dew point, and k represents the preset percentage coefficient, 0 < k < 1.

2. The method for controlling oxygen sensor heating and engine start-up without dew point according to claim 1, characterized in that: The preset proportion coefficient k = 0.

7.

3. The method for controlling oxygen sensor heating and engine start-up without dew point according to claim 1, characterized in that: If any one of conditions 1a to 1g is met, then the engine starting mode is determined to be prohibited from starting; where, Condition 1a is: the fuel level sensor is fault-free, the remaining fuel level in the fuel tank is less than or equal to the first preset fuel level threshold, and there is an engine torque output fault. Condition 1b is: there is a phase sensor fault or a generator fault; Condition 1c is: A request to prevent engine start is received for a speed sensor fault diagnosis. Condition 1d is: within the current key cycle, the number of consecutive engine start failures is greater than or equal to a preset threshold number. Condition 1e is: the vehicle's ready light is not on, the remaining fuel in the fuel tank is greater than the second preset fuel threshold, the front air volume adjustment signal is not OFF and no remote air conditioning start request or remote front defrost start request has been received, no AC gun discharge enable signal has been received, no camping mode start signal has been received, and no DC discharge gun connection signal has been received. Condition 1f is: receiving a request to unlock the fuel tank cap, and the vehicle speed is less than the first preset vehicle speed threshold; Condition 1g is: Driving mode is forced EV mode.

4. The method for controlling oxygen sensor heating and engine start-up without dew point according to claim 1, characterized in that: If condition 2a is met, the engine start mode is determined to be high priority start; where condition 2a is: the driver has a strong acceleration demand and needs to start the range extender.

5. The method for controlling oxygen sensor heating and engine start-up without dew point according to claim 4, characterized in that: If the accelerator pedal opening is greater than the preset opening threshold and continues for a preset time, it indicates that the driver has a strong acceleration demand. If the driver's original demand for driving power is greater than the difference between the available driving power and the preset power offset, then the range extender needs to be activated.

6. The method for controlling oxygen sensor heating and engine start-up without dew point according to claim 1, characterized in that: If condition 3a or 3b is met, the engine start mode is determined to be medium priority start; where, Condition 3a is: A parking charging request is received via the vehicle's infotainment system. Condition 3b is: A request for air conditioning to cool or heat is received, and the current battery power is insufficient to meet the request.

7. The method for controlling oxygen sensor heating and engine start-up without dew point according to claim 1, characterized in that: If any one of conditions 4a to 4c is met, the engine starting mode is determined to be low-priority start; where, Condition 4a is: the current actual SOC is less than the difference between the preset target maintained SOC and the preset SOC offset; Condition 4b is: the vehicle is not in forced EV mode, and the current actual SOC is less than the preset target maintenance SOC, and the vehicle speed is greater than the second preset vehicle speed threshold. Condition 4c is: receiving the winter mode activation signal and the vehicle speed is greater than the third preset vehicle speed threshold.

8. The method for controlling oxygen sensor heating and engine start-up without dew point according to claim 7, characterized in that: The third preset vehicle speed threshold is less than the second preset vehicle speed threshold.

9. A dew-point-free pre-oxygen sensor heating and engine starting control system, comprising a controller, characterized in that: The controller is configured to perform the dew-free pre-oxygen sensor heating and engine start control method as described in any one of claims 1 to 8.

10. A vehicle, characterized in that: This includes the dew-point-free oxygen sensor heating and engine start control system as described in claim 9.

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