Plateau low-temperature engine ISG motor gearbox joint control method

Abstract

The application discloses a plateau low-temperature engine ISG motor gearbox joint control method and relates to the control field of hybrid power vehicles. The method collects environmental temperature and altitude to calculate a comprehensive score, determines three-unit basic control parameters according to the score and performs ISG motor constraint correction; a time sequence relay strategy is adopted, the gearbox and the ISG motor respond first to make up for power gaps, and then the engine performs fuel injection compensation; in the execution process, the engine is constrained and corrected according to exhaust emission limitation, and the generated torque difference is distributed to the units with remaining capacity through mutual compensation rules to obtain final execution parameters; and finally, coordinated exit is performed. The application realizes multi-unit time sequence relay and dynamic mutual compensation, and significantly improves power response speed and compensation capacity under plateau low-temperature working conditions.

Description

Technical Field

[0001] This invention belongs to the field of hybrid vehicle control technology, and in particular relates to a method for joint control of an engine, ISG motor, and transmission in high-altitude and low-temperature environments. Background Technology

[0002] In high-altitude areas, air density decreases with altitude, leading to reduced engine air intake, incomplete combustion, and a significant drop in power output. Simultaneously, the low temperatures make engine starting difficult, prolong warm-up time, and further reduce combustion efficiency. The combined effect of these factors results in hybrid vehicles exhibiting sluggish power response and reduced acceleration performance under high-altitude, low-temperature conditions, severely impacting driving safety and comfort.

[0003] To address the issue of insufficient power under high-altitude and low-temperature conditions, existing technologies typically employ engine enrichment fuel injection to compensate for torque loss caused by insufficient air intake. However, relying solely on engine enrichment has the following drawbacks: First, the enrichment capacity is limited by exhaust emissions; excessive enrichment can lead to a sharp increase in carbon emissions. Second, the fuel injection compensation range is limited and insufficient to completely compensate for torque loss under extreme conditions. Third, enriched combustion reduces thermal efficiency and increases fuel consumption.

[0004] Some hybrid vehicles utilize the ISG (Integrated Starter Generator) motor to output auxiliary torque and improve power response in high-altitude and low-temperature environments. However, the output of the ISG motor is strictly constrained by the battery's state of charge (SOC), and its auxiliary capability is limited or even nonexistent when the battery charge is insufficient. Furthermore, current technologies lack deep coordination control between the engine and the ISG motor, resulting in suboptimal output matching. Simultaneously, existing technologies do not fully utilize the amplification effect of the transmission's shifting strategy on wheel-end torque, lacking an effective fallback compensation mechanism when both the engine and motor are physically constrained.

[0005] In summary, existing power compensation technologies for high-altitude and low-temperature conditions suffer from problems such as a single compensation unit, lack of timing and torque coordination among power sub-units, and insufficient consideration of physical constraints leading to limited overall compensation capabilities, making it difficult to meet the power demands of vehicles in extreme environments. Summary of the Invention

[0006] In view of this, the present invention aims to propose a joint control method for an engine, ISG motor, and transmission in high-altitude and low-temperature conditions, in order to solve the technical problems existing in the prior art, such as a single compensation unit, lack of coordination among various power sub-units, and insufficient consideration of physical constraints, which leads to limited vehicle power compensation capabilities and slow power response under high-altitude and low-temperature conditions.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows: This invention provides a method for joint control of an engine, ISG motor, and transmission under high-altitude and low-temperature conditions. It is applied to a vehicle powertrain system equipped with an engine, an ISG motor, and an automatic transmission. The vehicle powertrain system also includes a main controller, an engine ECU, a transmission TCU, a motor controller, and a sensor system. The method for joint control of the engine-ISG motor-transmission under high-altitude and low-temperature conditions includes the following steps: Step S1, Start-up phase: The ISG motor operates in electric mode, driving the engine crankshaft to rotate; when the speed reaches the idle speed condition and remains stable, the ignition is determined to be successful, and the ISG motor smoothly switches from electric mode to generator mode, and the engine enters the stable idle speed operation phase. Step S2, Condition Awareness and Risk Assessment Phase: Upon receiving an acceleration command, the ambient temperature is simultaneously collected via the sensor system. Altitude Engine speed and battery state of charge According to ambient temperature and altitude The overall score is calculated using a comprehensive scoring method. ,when The system will enter the joint assistance mode if a preset threshold is reached; otherwise, it will maintain the normal operation mode. Step S3, Basic Parameter Determination and ISG Motor Constraint Correction Stage: When it is determined that joint assistance is needed, the main controller determines the overall score. Determine the basic control parameters of the engine, ISG motor, and transmission; and based on the battery... Determine the maximum available torque of the ISG motor, constrain and correct the basic auxiliary torque, and obtain the actual auxiliary torque of the ISG motor and the torque difference generated by the ISG motor. Step S4, Timing Relay Coordinated Control Stage: The main controller sends control commands to the engine, ISG motor and transmission. Due to the different physical response speeds of each unit, the execution effects are presented sequentially in time: In the first stage, the transmission TCU executes a delayed upshift strategy, while the ISG motor switches to electric mode and outputs the actual auxiliary torque; In the second stage, the engine ECU executes high-altitude enrichment fuel injection compensation. Step S5, Engine Constraint Correction and Mutual Compensation Stage: During the timing relay coordinated control process, the basic compensation fuel injection quantity is constrained and corrected according to the exhaust smoke limit to obtain the actual fuel injection compensation quantity of the engine and the torque difference generated by the engine; based on the torque difference generated by the ISG motor and the torque difference generated by the engine, the difference is allocated to the units with remaining capacity in the engine, ISG motor or gearbox through the mutual compensation rule to obtain the final execution parameters of each unit; Step S6, Coordinated Exit Phase: When the exit conditions are met, the main controller performs coordinated exit, controls the rate of change of total output torque to not exceed the preset exit rate threshold, the ISG motor auxiliary torque and fuel injection compensation amount decrease synchronously, and finally restores the normal shifting logic of the gearbox.

[0008] Furthermore, in step S2, the comprehensive scoring method specifically includes: The altitude score and temperature score are added together to obtain the overall score. ; Altitude scoring rules: When Shi De divide; when Shi De divide; when Shi De point; Temperature scoring rules: When Shi De divide; when Shi De divide; when Shi De point; Based on the overall score Determine the working condition: when The time-sharing condition is determined to be an extreme working condition; when The time-based assessment classifies it as a medium-risk working condition; when The time-based assessment indicates a slightly risky working condition; when The system does not enter the joint assistance mode during time-sharing.

[0009] Furthermore, in step S3, the basic control parameters of the engine, ISG motor, and transmission are determined based on a comprehensive score. This is confirmed, specifically including: Basic upshift delay :when Time division ;when Time division ;when Time division ;in ; Basic auxiliary torque :when Time division ;when Time division ;when Time division ;in This is the engine's rated torque. ; Basic compensated fuel injection quantity :when Time division ;when Time division ;when Time division ;in This is the engine's base fuel injection quantity. .

[0010] Furthermore, in step S3, the maximum available torque of the ISG motor... According to the battery Sure: when hour, ; when hour, ; when hour, ; in This refers to the lower limit threshold for safe battery discharge. This refers to the battery's maximum discharge threshold. This refers to the peak torque of the ISG motor; The actual auxiliary torque of the ISG motor ; when At that time, the ISG motor generates a torque difference. .

[0011] Furthermore, in step S4, the specific timing sequence of the timing relay collaborative control is as follows: The first phase, with a time interval of [time period] to The transmission TCU executes a delayed upshift strategy with a response time of 10ms; at the same time, the ISG motor outputs the actual auxiliary torque within 10ms to 50ms. The second phase, with a time interval of [time period] to The engine ECU performs high-altitude enrichment fuel injection compensation, gradually increasing torque output within 100ms to 300ms; among which... .

[0012] Furthermore, in step S5, the engine constraint correction specifically involves: Actual fuel injection compensation of the engine ,in The maximum allowable fuel injection compensation amount is obtained by querying the preset exhaust limit MAP based on the current engine speed and load. when At that time, the engine produces a torque difference. ,in This is the fuel injection quantity to torque conversion coefficient.

[0013] Furthermore, in step S5, the specific rules for mutual assistance compensation are as follows: when and At that time, the difference is compensated by the engine, and the engine compensates for the amount of fuel injected. ; when and At that time, the difference is compensated by the ISG motor, and the ISG compensation torque... ; when and At that time, the total difference is compensated by the transmission, which additionally increases the upshift delay. ,in The torque conversion factor is obtained by querying the preset gear ratio MAP based on the current gear position; when and At that time, no mutual assistance compensation is required, and all compensation amounts are set to zero; The final execution parameter is: transmission upshift delay. ISG assist torque Engine fuel injection compensation amount .

[0014] Furthermore, in step S6, the exit condition includes: engine speed. Reaching the exit speed threshold And the duration of the combined assistance Achieve the shortest assistance time or combined auxiliary duration Reaching maximum assist time ; The coordinated exit will be carried out in the following sequence: Phase 1: The auxiliary torque of the ISG motor and the fuel injection compensation amount decrease synchronously in the same number of stages. After each stage of decrease, the engine speed fluctuation is monitored. If the fluctuation exceeds the limit, the decrease is stopped. Second stage: After the auxiliary torque drops to zero, it enters the zero torque range and maintains the preset synchronization time. Then, the generator torque is applied in reverse according to the preset slope, and the ISG motor smoothly switches from electric mode back to generator mode. Phase 3: After confirming that the engine speed is stable, the transmission TCU resumes normal shifting logic and cancels upshift delay.

[0015] Compared with existing technologies, the high-altitude cryogenic engine ISG motor-gear joint control method of the present invention has the following advantages: (1) Time-sequence relay collaboration, faster response speed: This invention makes full use of the physical response speed difference of each power unit. The gearbox delays upshifting almost instantly, and the ISG motor can output torque within tens of milliseconds. The two make up for the power gap within hundreds of milliseconds, and then the engine fuel injection compensation gradually catches up, realizing a fast power response.

[0016] (2) Three-unit joint compensation for better power response: By coordinating the three units of engine rich fuel injection, ISG motor auxiliary torque and gearbox delayed upshift, compared with single-unit compensation, it can provide more sufficient torque compensation under high-altitude and low-temperature conditions, and significantly improve the problem of insufficient power response.

[0017] (3) Strategy generation and constraint correction are separated, and the logic is clear: the basic parameters are determined only based on the severity of the working condition during the strategy generation stage, and the constraint correction and mutual compensation are handled in a unified manner during the execution stage. The two layers of logic are independent and do not overlap, and the system implementation is simple and reliable.

[0018] (4) Mutual assistance compensation is matched in the direction of the difference, and the compensation is accurate: depending on whether the engine and ISG motor generate physical constraint differences, the compensation task is directly assigned to the unconstrained unit. Whoever has spare capacity will compensate, rather than fixed priority scheduling, and the compensation amount is accurately matched with the difference.

[0019] (5) Graded intervention and allocation as needed: Based on the comprehensive score, three levels of control are implemented for mild, moderate and extreme working conditions to avoid excessive intervention in mild working conditions that would lead to increased fuel consumption, and to achieve a balance between power compensation and system cost.

[0020] (6) Battery SOC is automatically incorporated into constraint correction: Battery SOC directly affects the constraint correction result through the available maximum torque. When SOC is low, the ISG difference automatically enters the mutual compensation process, eliminating the need for a separate SOC decision branch and simplifying the control logic.

[0021] (7) Smooth and coordinated exit to avoid sudden torque changes: The exit process adopts a torque change rate limiting strategy, the total output torque change rate does not exceed the preset threshold, and the engine speed fluctuation is monitored in real time during the exit process. When the fluctuation exceeds the limit, the exit is paused to avoid vehicle jerking caused by sudden torque drop. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic flowchart of the overall control method provided in the embodiments of the present invention; Figure 2 This is a flowchart illustrating the mutual compensation provided in an embodiment of the present invention. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figures 1 to 2 As shown, the combined control method of high-altitude low-temperature engine ISG motor and gearbox includes the following steps: Step S1, Start-up phase: The ISG motor operates in electric mode, driving the engine crankshaft to rotate; when the speed reaches the idle speed condition and remains stable, the ignition is determined to be successful, and the ISG motor smoothly switches from electric mode to generator mode, and the engine enters the stable idle speed operation phase. Step S2, Condition Awareness and Risk Assessment Phase: Upon receiving an acceleration command, the ambient temperature is simultaneously collected via the sensor system. Altitude Engine speed and battery state of charge According to ambient temperature and altitude The overall score is calculated using a comprehensive scoring method. ,when The system will enter the joint assistance mode if a preset threshold is reached; otherwise, it will maintain the normal operation mode. Step S3, Basic Parameter Determination and ISG Motor Constraint Correction Stage: When it is determined that joint assistance is needed, the main controller determines the overall score. Determine the basic control parameters of the engine, ISG motor, and transmission; and based on the battery... Determine the maximum available torque of the ISG motor, constrain and correct the basic auxiliary torque, and obtain the actual auxiliary torque of the ISG motor and the torque difference generated by the ISG motor. Step S4, Timing Relay Coordinated Control Stage: The main controller sends control commands to the engine, ISG motor and transmission. Due to the different physical response speeds of each unit, the execution effects are presented sequentially in time: In the first stage, the transmission TCU executes a delayed upshift strategy, while the ISG motor switches to electric mode and outputs the actual auxiliary torque; In the second stage, the engine ECU executes high-altitude enrichment fuel injection compensation. Step S5, Engine Constraint Correction and Mutual Compensation Stage: During the timing relay coordinated control process, the basic compensation fuel injection quantity is constrained and corrected according to the exhaust smoke limit to obtain the actual fuel injection compensation quantity of the engine and the torque difference generated by the engine; based on the torque difference generated by the ISG motor and the torque difference generated by the engine, the difference is allocated to the units with remaining capacity in the engine, ISG motor or gearbox through the mutual compensation rule to obtain the final execution parameters of each unit; Step S6, Coordinated Exit Phase: When the exit conditions are met, the main controller performs coordinated exit, controls the rate of change of total output torque to not exceed the preset exit rate threshold, the ISG motor auxiliary torque and fuel injection compensation amount decrease synchronously, and finally restores the normal shifting logic of the gearbox.

[0028] The specific implementation method is as follows: System composition and hardware architecture The high-altitude, low-temperature engine-ISG motor-transmission joint control method provided in this embodiment is applied to the powertrain system of a hybrid vehicle equipped with an engine, an ISG (Integrated Starter Generator) motor, and an automatic transmission. This system mainly includes a main controller (VCU), an engine electronic control unit (ECU), a transmission control unit (TCU), a motor controller (MCU), and a sensor system. Each control unit communicates with the main controller via a controller area network (CAN) bus to achieve high-speed data exchange and command issuance. The CAN bus, acting as the vehicle's nerve center, ensures millisecond-level information synchronization between subsystems, which is crucial for the timing relay control mentioned later, guaranteeing the real-time performance and consistency of control commands.

[0029] The sensor system includes an altitude sensor, an ambient temperature sensor, a battery SOC (State of Charge) sensor, an engine speed sensor, and an exhaust oxygen sensor. The altitude sensor is used to monitor the vehicle's altitude in real time. Its data directly reflects changes in atmospheric pressure and air density, which in turn affect the engine's intake air volume; the ambient temperature sensor is used to collect the outside atmospheric temperature. This parameter affects intake air density, engine oil viscosity, and engine warm-up status; the battery SOC sensor is used to monitor the state of charge of the power battery. This is the key boundary condition that determines the output capability of the ISG motor; the engine speed sensor is used to collect the engine crankshaft speed. The starting and stopping conditions are determined by the start-up status and the exhaust oxygen sensor; the exhaust oxygen sensor is used to assist in determining the combustion status and exhaust limits, preventing excessive enrichment that could lead to excessive carbon emissions.

[0030] Overall flow of control methods like Figure 1 As shown, the overall flow of the control method in this embodiment includes steps S1 to S6. This flowchart embodies the control concept of sensing before decision-making, correcting before execution, relaying from fast to slow, and finally exiting smoothly, aiming to solve the problem of insufficient compensation capability of a single power source in high-altitude and low-temperature environments.

[0031] Step S1, Start-up phase.

[0032] The ISG motor operates in electric mode, driving the engine crankshaft. In high-altitude, low-temperature environments, the low air density and temperature result in low compression end-point temperatures and pressures within the engine cylinders, leading to starting difficulties. The high torque characteristics of the ISG motor play a crucial role in assisting starting during this phase, overcoming increased frictional resistance and establishing baseline oil pressure and coolant temperature. Once the engine speed reaches and stabilizes at idle, the system determines that ignition was successful. At this point, the ISG motor smoothly switches from electric mode to generator mode, and the engine enters a stable idling operation phase, providing a stable operating condition for subsequent integrated control.

[0033] Step S2, Condition Perception and Risk Assessment Phase.

[0034] When the main controller receives an acceleration command from the driver (such as the accelerator pedal opening exceeding a preset threshold), it synchronously collects the ambient temperature through the sensor system. Altitude Engine speed and battery state of charge The system adjusts according to ambient temperature. and altitude The overall score is calculated using a comprehensive scoring method. .

[0035] The specific rules of the comprehensive scoring method are as follows. These rules aim to quantify the comprehensive impact of high-altitude low temperatures on the power system and transform fuzzy environmental factors into definite control parameters: For altitude Rating: when At that time, air density decreased significantly (to about 70% of that at sea level), resulting in severely insufficient air intake and a sharp drop in combustion efficiency, scoring as follows: point; when At that time, the air density decreased moderately, and the dynamic force decreased to some extent, resulting in a score of [score missing]. point; when At that time, the impact was relatively small, and the score was [score missing]. point.

[0036] Regarding ambient temperature Rating: when At that time, the engine oil viscosity was extremely high, the combustion chamber wall temperature was low, and fuel atomization was poor, resulting in a score of [score missing]. point; when At that time, the effect of low temperature was significant, and the score was [score missing]. point; when At that time, the impact was relatively small, and the score was [score missing]. point.

[0037] The altitude score and temperature score are added together to obtain the overall score. .

[0038] Based on the overall score Determine the risk level of the working condition and decide on the control strategy: when When the time is divided into extreme working conditions, the power loss is severe. All three units will operate at the maximum compensation to ensure that the vehicle does not stall and has basic passability. when The time-sharing operation was determined to be a medium-risk condition, and the three units were executed with a medium compensation amount to balance power and economy. when When the condition is determined to be a low-risk operating condition, only the engine performs a slight fuel injection compensation and the ISG outputs a slight auxiliary torque, while the transmission maintains normal shifting logic to avoid unnecessary fuel consumption and emissions degradation. when During time-sharing, it does not enter the joint auxiliary mode and maintains the normal operation mode.

[0039] Step S3: Basic parameter determination and ISG motor constraint correction stage.

[0040] like Figure 1 As shown, when it is determined that joint assistance is needed (i.e. The main controller first determines the overall score. The basic control parameters of the three units are determined, and constraint correction of the ISG motor is performed immediately. This is because the ISG motor has an extremely fast response (millisecond level), and its available torque is limited by the battery SOC. It must be known before the timing relay start-up in order to calculate the difference later.

[0041] The three basic control parameters are based on the overall score. The specific formula is as follows: Basic upshift delay Determination: (1); In the above formula, when Time-sharing ; (2); In the above formula, when Time-sharing ; (3); In the above formula, when Time-sharing .

[0042] in This is the normal upshift speed threshold. .

[0043] Basic auxiliary torque Determination: (4); In the above formula, when Time-sharing ; (5); In the above formula, when Time-sharing ; (6); In the above formula, when Time-sharing .

[0044] in The rated torque of the engine. .

[0045] Basic compensated fuel injection quantity Determination: (7); In the above formula, when Time-sharing ; (8); In the above formula, when Time-sharing ; (9); In the above formula, when Time-sharing .

[0046] in This is the engine's base fuel injection quantity. .

[0047] Next, the maximum available torque of the ISG motor is determined. The determination and correction of this value are based on the battery. Sure: when At that time, the battery was fully charged. (10); in This represents the peak torque of the ISG motor. This is the lower limit threshold for safe battery discharge.

[0048] when When the battery is low but still capable of discharging, a linear interpolation method is used to calculate the available torque to prevent over-discharge. (11); in This is the battery's maximum discharge threshold, and .

[0049] when At this time, the battery level is extremely low. To protect battery life and safety: (12); Calculate the actual auxiliary torque of the ISG motor : (13); like The ISG motor will then generate a torque difference: (14); like ,but .

[0050] Step S4, the timing relay collaborative control stage.

[0051] like Figure 1 As shown, after the basic parameters are determined and the ISG motor is calibrated, the main controller sends control commands to the three units. Since the physical response speeds of each unit differ significantly, this invention employs a timing relay strategy to maximize response speed.

[0052] The first phase, with a time interval of [time period] to The transmission TCU and ISG motor execute the strategy first. The transmission TCU implements a delayed upshift strategy, which essentially modifies the upshift speed threshold in the software parameters, with a response time of 10ms, taking effect almost instantly. By delaying the upshift, the vehicle can maintain a low gear, utilizing the high gear ratio of the low gear to amplify the wheel-end torque. Simultaneously, the ISG motor switches from generator mode to electric mode, outputting actual auxiliary torque within 10ms to 50ms. Note: The output here is the actual torque after correction in step S3, not the base torque, to first make up for the power gap.

[0053] The second phase, with a time interval of [time period] to The engine ECU performs high-altitude enrichment fuel injection compensation. Because the engine involves physical and chemical processes such as intake, fuel injection, atomization, and combustion, its response is relatively slow, typically gradually increasing torque output over 100ms to 300ms. The timing parameters for each stage are determined based on the overall score. The classification is determined.

[0054] Step S5, Engine constraint correction and mutual compensation stage.

[0055] like Figure 1 and Figure 2 As shown, during the timing relay coordinated control process, especially during the engine fuel injection compensation execution process, the main controller further corrects the basic control parameters based on the engine's physical constraints and performs mutual compensation.

[0056] The actual fuel injection compensation of the engine is limited by the smoke limit (i.e., the smoke emission regulation limit): (15); in The main controller obtains the maximum allowable fuel injection compensation amount by querying the preset exhaust limit MAP based on the engine's current speed and load.

[0057] Calculate the torque difference generated by the engine: when hour: (16); in This is the fuel injection quantity-torque conversion coefficient. If... ,but .

[0058] like Figure 2 As shown, the mutual assistance compensation judgment process then begins. The core idea of ​​this invention is that whoever has the surplus capacity should compensate, and the specific rules are as follows: Scenario 1, when and This indicates that the engine is not limited by exhaust emission restrictions and is capable of compensating for the torque shortfall caused by insufficient ISG battery power. The difference is compensated by the engine, specifically the amount of fuel injection used for engine compensation: (17); Scenario 2, when and This indicates that the ISG motor has sufficient power and is capable of compensating for the torque shortfall caused by engine exhaust limitations. The difference is compensated by the ISG motor, and the ISG compensation torque is: (18); Scenario 3, when and This indicates that both the engine and ISG motor are limited (both lacking power and with restricted exhaust), which is the worst-case scenario. In this case, the total difference is compensated by the transmission. The transmission compensates by additionally increasing the upshift delay, utilizing the high gear ratio of the lower gear to amplify the wheel-end torque as a fallback compensation mechanism. The transmission additionally increases the upshift delay as follows: (19); in This is to retrieve the torque conversion factor from the transmission ratio MAP based on the current gear. The lower the gear, the larger the gear ratio, and the more significant the torque amplification effect. The smaller the value.

[0059] Scenario 4, when and This indicates that each unit can meet its basic needs and no mutual compensation is required. At this point, the compensation amounts... , , All are set to zero.

[0060] The final execution parameters of each unit after correction and mutual compensation are calculated as follows: Upshift delay of the transmission: (20); ISG auxiliary torque: (twenty one); Engine fuel injection compensation amount: (twenty two); Step S6, Coordinated Exit Phase.

[0061] like Figure 1 As shown, the main controller performs a coordinated exit when the exit conditions are met. The exit conditions include: engine speed... Reaching the exit speed threshold And the duration of the combined assistance Achieve the shortest assistance time or combined auxiliary duration Reaching maximum assist time .

[0062] The coordinated exit will be carried out in the following sequence, with the core idea being a smooth transition and avoiding any abrupt changes: Exit rate control: Rate of change of total output torque Not exceeding the preset exit rate threshold .

[0063] In the first stage, the ISG motor's auxiliary torque and fuel injection compensation amount decrease synchronously in the same increments, maintaining a preset steady-speed period after each torque reduction. After each reduction, engine speed fluctuations are monitored; if the fluctuation exceeds a preset fluctuation threshold, the reduction is paused, maintaining the current compensation amount until the speed stabilizes before resuming the reduction. This mechanism prevents vehicle jerking or engine stalling caused by a sudden withdrawal of torque.

[0064] In the second stage, after the auxiliary torque drops to zero, it enters the zero torque range and maintains a preset synchronization time. Then, it applies the generator torque in the opposite direction according to a preset slope, and the ISG motor smoothly switches from electric mode back to generator mode.

[0065] In the third stage, after confirming that the engine speed is stable, the transmission TCU resumes normal shifting logic and cancels the upshift delay.

[0066] Parameter definition description To facilitate understanding of the above embodiments, the parameters involved in the specific implementation process are defined and explained below: Engine rated torque .

[0067] ISG motor peak torque .

[0068] Engine base fuel injection quantity .

[0069] Normal upshift speed threshold .

[0070] Fuel injection quantity - torque conversion coefficient .

[0071] Taking 3rd gear as an example, .

[0072] Injection compensation coefficient: , , .

[0073] ISG auxiliary torque coefficient: , , .

[0074] Upshift delay factor: , .

[0075] Battery safe discharge lower limit threshold .

[0076] Battery discharge limit threshold .

[0077] Exhaust smoke limit: maximum permissible fuel injection compensation amount .

[0078] Speed ​​fluctuation threshold .

[0079] Example 1: Medium-altitude operating conditions, with sufficient battery power The operating conditions in this embodiment are: altitude Ambient temperature ,Battery .

[0080] The process is explained as follows: Overall score calculation: Altitude In to Between, scores Points; ambient temperature In to Between, scores Points. Overall score. The condition has been determined to be of medium risk, and the system has entered joint auxiliary mode.

[0081] Step S3 is performed (basic parameters and ISG calibration): According to formula (2), the basic upshift delay amount .

[0082] According to formula (5), the basic auxiliary torque .

[0083] According to formula (8), the basic compensation injection quantity .

[0084] because According to formula (10), .

[0085] According to formula (13), .at this time .

[0086] Step S4 execution (timing relay): In the first stage, the transmission TCU raises the upshift speed threshold to ISG motor output Actual auxiliary torque.

[0087] The second stage involves the overlay of the engine ECU. Fuel injection quantity.

[0088] Step S5 is executed (engine calibration and assistance): Sure According to formula (15), .at this time .

[0089] because and This falls under scenario four, and no mutual assistance compensation is required.

[0090] Final execution parameters: transmission delay ISG torque Fuel injection compensation .

[0091] Coordinated Exit: When the engine speed reaches And duration Exit at that time.

[0092] Example 2: Extreme high-altitude operating conditions, insufficient battery power The operating conditions in this embodiment are: altitude Ambient temperature ,Battery .

[0093] The process is explained as follows: Overall score calculation: The condition is classified as an extreme working condition.

[0094] Step S3 is executed: Basic parameters: , , .

[0095] ISG correction: According to formula (11), .

[0096] According to formula (13), A difference arises. .

[0097] Step S4 is executed: In the first phase, the transmission threshold is increased to... ISG output .

[0098] The second stage involves engine stacking. .

[0099] Step S5 is executed: Engine calibration: A difference arises. .

[0100] Mutual assistance and compensation: and This falls under scenario three, and is compensated by the gearbox.

[0101] According to formula (19), .

[0102] Final parameter: Transmission delay (threshold) ), ISG torque Oil spraying .

[0103] Example 3: Extreme high-altitude operating conditions, with extremely low battery power. The operating conditions in this embodiment are: altitude Ambient temperature ,Battery .

[0104] The process is explained as follows: Overall score point.

[0105] Step S3 is executed: The basic parameters are the same as above (extreme operating conditions).

[0106] ISG correction: According to formula (12), .

[0107] A difference arises. .

[0108] Step S4 is executed: In the first stage, only the transmission responds (ISG has no torque).

[0109] The second stage involves engine stacking. .

[0110] Step S5 is executed: Engine calibration: . .

[0111] Mutual assistance and compensation: and This is compensated by the gearbox.

[0112] .

[0113] Final parameter: Transmission delay (threshold) ), ISG torque Oil spraying .

[0114] Example 4: Exit Process Description When the exit conditions are met, the main controller will exit according to the following sequence: In the first stage, the ISG auxiliary torque and fuel injection compensation amount decrease synchronously in stages of the same level, with their deceleration rates kept matched to ensure a smooth decrease in total auxiliary torque and avoid abrupt changes. Engine speed is monitored in real time during the decrease; if the speed drops by more than [a certain amount], [further action is taken]. The reduction will then pause, maintaining the current compensation amount until the engine speed stabilizes, at which point the reduction will resume. When the auxiliary torque of the ISG and engine drops to zero, the second stage begins.

[0115] In the second stage, the ISG maintains its position in the zero-torque range. Synchronize time, then press The slope is reversed to apply the generating torque, and the ISG motor smoothly switches from electric mode back to generating mode.

[0116] The third stage involves confirming that engine speed fluctuations do not exceed [the specified range]. And continue Afterwards, the transmission TCU resumes normal shifting logic, gradually reduces upshift delay, and finally eliminates upshift delay, completing the exit.

[0117] In summary, the high-altitude low-temperature engine ISG motor-transmission joint control method provided by this invention, through deep integration of environmental perception, timing control, and dynamic torque distribution, completely changes the traditional extensive compensation mode that relies solely on engine enrichment or simple motor assistance. Compared with the prior art, this invention has the following significant advantages: First, a time-series relay strategy achieves millisecond-level rapid power response, filling power gaps. This invention fully utilizes the differences in physical response speeds among the various sub-units in the vehicle's powertrain. At the instant the acceleration command is issued, the transmission TCU modifies software parameters to achieve an immediate upshift with a delay of approximately 10ms, amplifying wheel-end torque using a lower gear with a higher speed ratio; simultaneously, the ISG motor rapidly outputs actual auxiliary torque within 10ms to 50ms. These two components first fill the power gap within hundreds of milliseconds, followed by the engine ECU gradually increasing fuel injection compensation within 100ms to 300ms. This "electric / mechanical first, fuel later" time-series relay strategy effectively eliminates the power lag caused by slow engine response in traditional control systems, achieving an extremely rapid power response.

[0118] Secondly, the dynamic mutual compensation under multiple physical constraints breaks through the compensation limit of a single unit and provides a safety net. In extreme conditions such as high altitude and low temperatures, the ISG motor is limited by battery SOC, and the engine is limited by exhaust emissions, often failing to output ideal torque. This invention innovatively introduces a constraint correction and mutual compensation mechanism. When a unit experiences a torque difference due to physical constraints, the system can allocate the difference to unconstrained units according to the principle of "whoever has spare capacity compensates." Especially in the worst-case scenario where both the engine and ISG motor are limited, this invention can automatically utilize the additional upshift delay of the transmission, using the mechanical transmission characteristics of the transmission for safety net compensation. This multi-unit joint mutual assistance mechanism completely solves the problem of overall power compensation failure caused by the limitation of a single unit in existing technologies.

[0119] Third, the system employs a tiered, on-demand control based on a comprehensive score, balancing power performance with economic and environmental considerations. This invention abandons a one-size-fits-all compensation strategy. By constructing a comprehensive scoring model based on altitude and ambient temperature, it quantifies complex high-altitude, low-temperature conditions into three risk levels: extreme, moderate, and mild. The system dynamically adjusts the basic upshift delay, basic auxiliary torque, and basic compensation fuel injection based on the comprehensive score S. Under mild-risk conditions, only minor compensation is applied while maintaining normal transmission logic, avoiding increased fuel consumption and carbon emissions caused by excessive intervention. Under extreme conditions, full power output is achieved. This tiered intervention mechanism achieves an optimal balance between power compensation and system costs while ensuring vehicle passability.

[0120] Fourth, the decoupling of strategy generation and constraint execution enhances system robustness and engineering reliability. The control logic of this invention clearly separates basic parameter generation from physical constraint correction. The strategy generation phase determines the basic parameters under ideal conditions based solely on environmental conditions, while constraint correction and mutual compensation are handled uniformly during the execution phase. This two-layer, independent, and non-overlapping architecture significantly reduces the real-time computational load on the main controller and also results in highly modular control code. When vehicle hardware parameters (such as battery degradation or engine aging) change, only the constraint correction module needs adjustment; there is no need to reconstruct the basic strategy, significantly improving system robustness and post-calibration efficiency.

[0121] Fifth, a smooth and coordinated exit mechanism significantly improves driving comfort and safety. When exiting the combined assist mode, this invention does not use a direct, abrupt method of cutting off compensation. Instead, it introduces a total output torque change rate limit and a real-time engine speed fluctuation monitoring mechanism. During the synchronous reduction of ISG assist torque and fuel injection compensation, if engine speed fluctuations exceed the limit, the system immediately pauses the reduction and maintains the current compensation amount until the speed stabilizes before continuing to exit. Simultaneously, the ISG motor achieves a seamless and smooth switch from electric mode to generator mode by maintaining zero torque and applying reverse torque generation. This series of coordinated exit strategies effectively avoids vehicle jerking, hesitation, or even engine stalling caused by sudden torque withdrawal, greatly improving driving comfort and safety in high-altitude and low-temperature environments.

[0122] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for joint control of an engine, ISG motor, and automatic transmission in high-altitude, low-temperature environments, applied to a vehicle powertrain system equipped with an engine, an ISG motor, and an automatic transmission, wherein the vehicle powertrain system further includes a main controller, an engine ECU, a transmission TCU, a motor controller, and a sensor system, characterized in that... The combined control method of engine-ISG motor-transmission under high-altitude and low-temperature conditions includes the following steps: Step S1, Start-up phase: The ISG motor operates in electric mode, driving the engine crankshaft to rotate; when the speed reaches the idle speed condition and remains stable, the ignition is determined to be successful, and the ISG motor smoothly switches from electric mode to generator mode, and the engine enters the stable idle speed operation phase. Step S2, Condition Awareness and Risk Assessment Phase: Upon receiving an acceleration command, the ambient temperature is simultaneously collected via the sensor system. Altitude Engine speed and battery state of charge According to ambient temperature and altitude The overall score is calculated using a comprehensive scoring method. ,when The system will enter the joint assistance mode if a preset threshold is reached; otherwise, it will maintain the normal operation mode. Step S3, Basic Parameter Determination and ISG Motor Constraint Correction Stage: When it is determined that joint assistance is needed, the main controller determines the overall score. Determine the basic control parameters of the engine, ISG motor, and transmission; and based on the battery... Determine the maximum available torque of the ISG motor, constrain and correct the basic auxiliary torque, and obtain the actual auxiliary torque of the ISG motor and the torque difference generated by the ISG motor. Step S4, Timing Relay Coordinated Control Stage: The main controller sends control commands to the engine, ISG motor and transmission. Due to the different physical response speeds of each unit, the execution effects are presented sequentially in time: In the first stage, the transmission TCU executes a delayed upshift strategy, while the ISG motor switches to electric mode and outputs the actual auxiliary torque; In the second stage, the engine ECU executes high-altitude enrichment fuel injection compensation. Step S5, Engine Constraint Correction and Mutual Compensation Stage: During the timing relay coordinated control process, the basic compensation fuel injection quantity is constrained and corrected according to the exhaust smoke limit to obtain the actual fuel injection compensation quantity of the engine and the torque difference generated by the engine; based on the torque difference generated by the ISG motor and the torque difference generated by the engine, the difference is allocated to the units with remaining capacity in the engine, ISG motor or gearbox through the mutual compensation rule to obtain the final execution parameters of each unit; Step S6, Coordinated Exit Phase: When the exit conditions are met, the main controller performs coordinated exit, controls the rate of change of the total output torque to not exceed the preset exit rate threshold, the ISG motor auxiliary torque and the fuel injection compensation amount decrease synchronously, and finally restores the normal shifting logic of the gearbox. In step S2, the comprehensive scoring method is specifically as follows: The altitude score and temperature score are added together to obtain the overall score. ; Altitude scoring rules: When Shi De divide; when Shi De divide; when Shi De point; Temperature scoring rules: When Shi De divide; when Shi De divide; when Shi De point; Based on the overall score Determine the working condition: when The time-sharing condition is determined to be an extreme working condition; when The time-based assessment classifies it as a medium-risk working condition; when The time-based assessment indicates a slightly risky working condition; when The system does not enter the joint assistance mode during time-sharing.

2. The combined control method for a high-altitude cryogenic engine ISG motor and gearbox according to claim 1, characterized in that, In step S3, the basic control parameters of the engine, ISG motor, and transmission are determined based on the comprehensive score. This is confirmed, specifically including: Basic upshift delay :when Time division ;when Time division ;when Time division ;in ; Basic auxiliary torque :when Time division ;when Time division ;when Time division ;in This is the engine's rated torque. ; Basic compensated fuel injection quantity :when Time division ;when Time division ;when Time division ;in This is the engine's base fuel injection quantity. .

3. The combined control method for a high-altitude cryogenic engine ISG motor and gearbox according to claim 2, characterized in that, In step S3, the maximum available torque of the ISG motor is... According to the battery Sure: when hour, ; when hour, ; when hour, ; in This is the lower limit threshold for safe battery discharge. This refers to the battery's maximum discharge threshold. This refers to the peak torque of the ISG motor; The actual auxiliary torque of the ISG motor ; when At that time, the ISG motor generates a torque difference. .

4. The combined control method for a high-altitude cryogenic engine ISG motor and gearbox according to claim 1, characterized in that, In step S4, the specific timing sequence of the timing relay collaborative control is as follows: The first phase, with a time interval of [time period] to The transmission TCU executes a delayed upshift strategy with a response time of 10ms; at the same time, the ISG motor outputs the actual auxiliary torque within 10ms to 50ms. The second phase, with a time interval of [time period] to The engine ECU performs high-altitude enrichment fuel injection compensation, gradually increasing torque output within 100ms to 300ms; among which... .

5. The combined control method for a high-altitude cryogenic engine ISG motor and gearbox according to claim 3, characterized in that, In step S5, the engine constraint correction specifically involves: Actual fuel injection compensation of the engine ,in The maximum allowable fuel injection compensation amount is obtained by querying the preset exhaust limit MAP based on the current engine speed and load; when At that time, the engine produces a torque difference. ,in This is the fuel injection quantity to torque conversion coefficient.

6. The combined control method for a high-altitude cryogenic engine ISG motor and gearbox according to claim 5, characterized in that, In step S5, the specific rules for mutual assistance compensation are as follows: when and At that time, the difference is compensated by the engine, and the engine compensates for the amount of fuel injected. ; when and At that time, the difference is compensated by the ISG motor, and the ISG compensation torque... ; when and At that time, the total difference is compensated by the transmission, which additionally increases the upshift delay. ,in The torque conversion factor is obtained by querying the preset gear ratio MAP based on the current gear position; when and At that time, no mutual assistance compensation is required, and all compensation amounts are set to zero; The final execution parameter is: transmission upshift delay. ISG assist torque Engine fuel injection compensation amount .

7. The combined control method for a high-altitude cryogenic engine ISG motor and gearbox according to claim 1, characterized in that, In step S6, the exit conditions include: engine speed. Reaching the exit speed threshold And the duration of the combined assistance Achieve the shortest assistance time or combined auxiliary duration Reaching maximum assist time ; The coordinated exit will be carried out in the following sequence: Phase 1: The auxiliary torque of the ISG motor and the fuel injection compensation amount decrease synchronously in the same number of stages. After each stage of decrease, the engine speed fluctuation is monitored. If the fluctuation exceeds the limit, the decrease is stopped. Second stage: After the auxiliary torque drops to zero, it enters the zero torque range and maintains the preset synchronization time. Then, the generator torque is applied in reverse according to the preset slope, and the ISG motor smoothly switches from electric mode back to generator mode. Phase 3: After confirming that the engine speed is stable, the transmission TCU resumes normal shifting logic and cancels upshift delay.

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