Diesel engine ISG system plateau low temperature auxiliary speed-up control method

Abstract

The application discloses a plateau low-temperature auxiliary speed-up control method for a diesel engine ISG system. The method is applied to a diesel engine starting and generating integrated system and comprises the following steps: after the diesel engine is started, an ISG motor is operated in a power generation mode; when an acceleration instruction is received, environmental temperature and altitude parameters are collected; whether the diesel engine has a speed-up lag risk is evaluated by using a comprehensive scoring method; when the comprehensive score is greater than or equal to 1, the ISG motor is smoothly switched from the power generation mode to an electric mode, and auxiliary torque is output to help the diesel engine speed up; when the exit condition is met, the auxiliary torque is gradually reduced to zero, and after synchronization in the zero-torque interval, the auxiliary torque is reversely changed into power generation torque, and the smooth switching of the ISG motor from the electric mode to the power generation mode is completed. The application effectively solves the speed-up lag problem of the diesel engine caused by insufficient intake air during the acceleration process in a plateau low-temperature environment, and improves the environmental adaptability and reliability of the diesel engine ISG system.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine starter-generator (ISG) control technology, and in particular relates to a method for high-altitude and low-temperature auxiliary acceleration control of diesel engine ISG systems. Background Technology

[0002] An integrated starter generator (ISG) is an integrated electric motor system that combines the functions of an electric motor and a generator. In traditional applications, the ISG system operates primarily in two phases: the starting phase and the generator phase. During the starting phase, the motor operates as an electric motor, driving the diesel engine crankshaft to its ignition speed to complete the starting process. During the generator phase, after successful ignition of the diesel engine, the motor switches to generator mode, driven by the diesel engine to generate electricity and power the vehicle's electrical system.

[0003] However, traditional ISG systems have a significant technical flaw: after the diesel engine successfully ignites, the electric motor immediately switches to generator mode, without considering the potential acceleration difficulties the diesel engine may face after starting. This flaw is particularly pronounced under harsh operating conditions such as high altitudes and low temperatures.

[0004] When the altitude exceeds 2km, the decrease in atmospheric pressure and air density due to the increased altitude leads to insufficient air intake, causing a noticeable sluggishness in the diesel engine during acceleration. Under low-temperature conditions, increased oil viscosity and poor fuel atomization further exacerbate the acceleration difficulties. Even if the diesel engine has successfully ignited at this point, its output torque is still insufficient to quickly drive it to its rated speed.

[0005] Current solutions to the problem of acceleration at low temperatures in high-altitude areas mainly include adjusting fuel injection parameters, adding intake preheating devices, and using high-altitude turbochargers. However, none of these solutions involve the technical approach of using an ISG motor for auxiliary acceleration control, indicating a significant technological gap.

[0006] Patent searches revealed that existing ISG-related patents all focus on optimizing control strategies during the starting phase, such as starting speed control and starting torque optimization, without addressing auxiliary control technologies for the acceleration phase. Therefore, there is an urgent need in this field for a control method that can fill this technological gap and utilize an electric motor to assist in acceleration after the diesel engine starts. This would solve the problem of difficulty in accelerating diesel engines under harsh conditions such as high altitudes and low temperatures, and improve the environmental adaptability and reliability of diesel engine ISG systems. Summary of the Invention

[0007] In view of this, the present invention aims to propose a high-altitude and low-temperature assisted acceleration control method for diesel engine ISG systems, in order to solve the technical problem in the prior art where the diesel engine integrated starter (ISG) system is unable to quickly increase its speed after successful ignition due to insufficient intake air volume and increased frictional resistance, resulting in acceleration stagnation. At the same time, it fills the technical gap in the existing ISG system that lacks electric motor-assisted acceleration control technology during the acceleration phase after starting.

[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows: This invention provides a high-altitude, low-temperature auxiliary acceleration control method for a diesel engine ISG system, applied to a diesel engine starter-generator system. The diesel engine starter-generator system includes a main controller, an ISG motor, a motor controller, a diesel engine ECU, and a sensor system. The high-altitude, low-temperature auxiliary acceleration control method for the diesel engine ISG system includes the following steps: Step 1, Start-up phase: The ISG motor operates in electric mode, driving the diesel engine crankshaft to rotate; when the speed reaches the idle speed condition and remains stable, it is considered that the diesel engine has been successfully ignited. The ISG motor linearly reduces the starting torque to zero according to the preset slope, smoothly switching from electric mode to generator mode, and enters normal generator operation. Step 2, Operating Condition Sensing Phase: Upon receiving an acceleration command, the ambient temperature is synchronously collected via the sensor system. Altitude Real-time speed of diesel engine ; Step 3, Stagnation Risk Assessment Stage: Based on the collected ambient temperature data... and altitude A comprehensive scoring method was used to assess whether the diesel engine had a risk of acceleration lag. Altitude and ambient temperature were mapped to risk scores, which were then summed to obtain a comprehensive score. When the comprehensive score... If the system is set to enter auxiliary speed-up mode, it will enter normal power generation mode; otherwise, it will maintain normal power generation mode. Step 4, Assisted Acceleration Phase: When assistance is required, the ISG motor gradually reduces the generating torque to zero at a gentle slope. After the generating torque drops to zero, it enters the zero torque range and maintains synchronization for a preset time. Subsequently, the auxiliary torque is gradually increased at a preset slope until... This enables a seamless switching from power generation mode to electric mode; the ISG motor outputs auxiliary torque. The auxiliary torque helps the diesel engine accelerate quickly; Determined based on the overall score, categorized into different tiers; Step 5, Exit the judgment phase: Continuously monitor the diesel engine speed. and duration of assistance When the exit conditions are met, the mode switching phase begins; the exit conditions include: rotational speed. Reaching the exit speed threshold And the duration of the assistance Achieve the shortest assistance time Or the duration of the assistance Reaching maximum assist time ; Step 6, Mode Switching Stage: The auxiliary torque... The torque is gradually reduced in multiple stages, and a preset steady speed time is maintained after each stage of torque reduction. After the auxiliary torque drops to zero, it enters the zero torque range and maintains a preset synchronization time. Then, the generator torque is applied in reverse according to a preset slope to complete the smooth switching of the ISG motor from electric mode to generator mode.

[0009] Furthermore, in step 3, the specific scoring rules are as follows: For altitude :when When, 2 points are scored; when When, 1 point is awarded; when At that time, 0 points were awarded; For ambient temperature :when When, 2 points are scored; when When, 1 point is awarded; when At that time, 0 points were awarded; The auxiliary torque gear is determined based on the overall score: when the overall score is... The time-sharing process is judged as an extreme working condition; when the overall score is... The timeframe was determined to be a medium-risk working condition; when the overall score... The timeframe was determined to be a low-risk condition; when the overall score... The time-sharing process is considered a normal operating condition.

[0010] Furthermore, in step 4, the auxiliary torque The calculation formula is as follows: When the overall score Time-sharing ; When the overall score Time-sharing ; When the overall score Time-sharing ; in, The rated torque of the diesel engine. , , As the auxiliary torque coefficient, and .

[0011] Furthermore, the auxiliary torque coefficient , , .

[0012] Furthermore, in step 5, the exit speed threshold... For the target operating speed of the diesel engine to The shortest assistance time is times that of the previous one. for to seconds, the maximum auxiliary time for to Second.

[0013] Furthermore, in step 6, the auxiliary torque decreases in stages as follows: to Each stage has a torque reduction and a settling time of [time value missing]. to The synchronization time in the zero torque range is... to .

[0014] Furthermore, the synchronization time in the zero-torque range is selected based on the magnitude of the auxiliary torque: the larger the auxiliary torque, the longer the required synchronization time; specifically, when the auxiliary torque is... At that time, the synchronization time is taken When the auxiliary torque is At that time, the synchronization time is taken When the auxiliary torque is At that time, the synchronization time is taken .

[0015] Furthermore, in step 1, during the startup process, the motor controller employs closed-loop speed control, and the target operating speed is set to... When the speed fluctuation is less than continued At a certain time, it is determined to be stable.

[0016] Furthermore, the sensor system includes a temperature sensor, an altitude sensor, and a speed sensor, which are used to collect ambient temperature data in real time. Altitude and the real-time speed of the diesel engine The main controller is connected to the motor controller, diesel engine ECU, and sensor system via CAN bus communication.

[0017] Compared with existing technologies, the high-altitude low-temperature assisted acceleration control method for diesel engine ISG systems described in this invention has the following advantages: 1. Effectively solves the acceleration lag problem in high-altitude and low-temperature environments. This invention introduces ISG motor auxiliary torque during the diesel engine acceleration phase, effectively compensating for insufficient diesel engine output torque caused by insufficient air intake at high altitudes and low temperatures, enabling the diesel engine to quickly complete the acceleration process under harsh operating conditions. At altitudes above 3000m and ambient temperatures of -10℃, acceleration time can be reduced by more than 40%, significantly expanding the applicability of the ISG system.

[0018] 2. Improve the reliability and stability of the power system. This invention avoids problems such as weak acceleration and slow response of diesel engines caused by acceleration lag, ensuring the power output of the vehicle in complex environments and improving the reliability and stability of the entire power system.

[0019] 3. High degree of intelligence and adaptability in control logic. This invention intelligently judges the risk of lag through a comprehensive scoring method based on multiple parameters (ambient temperature, altitude), and automatically determines whether to enter the auxiliary mode and the level of auxiliary torque, without the need for manual intervention, thus achieving intelligent and adaptive control strategy.

[0020] 4. Smooth mode switching, avoiding system shock. This invention employs control strategies such as gradual torque transition, graded torque reduction, and synchronization within the zero-torque range when switching between power generation and electric modes. This effectively avoids the impact of sudden speed changes and electromagnetic oscillations on the system, ensuring smooth and safe system operation.

[0021] 5. Excellent technical compatibility and economic efficiency. This invention can be implemented on the existing ISG system hardware architecture through software upgrades only, without increasing additional hardware costs. It has excellent technical compatibility, economic efficiency, and engineering promotion value. 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 schematic diagram of the ISG-assisted speed-up timing provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the overall system structure 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 3 As shown, the high-altitude low-temperature auxiliary acceleration control method for diesel engine ISG system includes the following steps: Step 1, Start-up phase: The ISG motor operates in electric mode, driving the diesel engine crankshaft to rotate; when the speed reaches the idle speed condition and remains stable, it is considered that the diesel engine has been successfully ignited. The ISG motor linearly reduces the starting torque to zero according to the preset slope, smoothly switching from electric mode to generator mode, and enters normal generator operation. Step 2, Operating Condition Sensing Phase: Upon receiving an acceleration command, the ambient temperature is synchronously collected via the sensor system. Altitude Real-time speed of diesel engine ; Step 3, Stagnation Risk Assessment Stage: Based on the collected ambient temperature data... and altitude A comprehensive scoring method was used to assess whether the diesel engine had a risk of acceleration lag. Altitude and ambient temperature were mapped to risk scores, which were then summed to obtain a comprehensive score. When the comprehensive score... If the system is set to enter auxiliary speed-up mode, it will enter normal power generation mode; otherwise, it will maintain normal power generation mode. Step 4, Assisted Acceleration Phase: When assistance is required, the ISG motor gradually reduces the generating torque to zero at a gentle slope. After the generating torque drops to zero, it enters the zero torque range and maintains synchronization for a preset time. Subsequently, the auxiliary torque is gradually increased at a preset slope until... This enables a seamless switching from power generation mode to electric mode; the ISG motor outputs auxiliary torque. The auxiliary torque helps the diesel engine accelerate quickly; Determined based on the overall score, categorized into different tiers; Step 5, Exit the judgment phase: Continuously monitor the diesel engine speed. and duration of assistance When the exit conditions are met, the mode switching phase begins; the exit conditions include: rotational speed. Reaching the exit speed threshold And the duration of the assistance Achieve the shortest assistance time Or the duration of the assistance Reaching maximum assist time ; Step 6, Mode Switching Stage: The auxiliary torque... The torque is gradually reduced in multiple stages, and a preset steady speed time is maintained after each stage of torque reduction. After the auxiliary torque drops to zero, it enters the zero torque range and maintains a preset synchronization time. Then, the generator torque is applied in reverse according to a preset slope to complete the smooth switching of the ISG motor from electric mode to generator mode.

[0028] The specific implementation method is as follows: This invention provides a method for high-altitude, low-temperature auxiliary acceleration control of a diesel engine ISG system. For example... Figure 3 As shown, this method is applied to a diesel engine starter system, which mainly includes a main controller, a motor controller, a diesel engine ECU, and a sensor system. The main controller, as the core computing unit, is responsible for condition sensing, speed lag risk assessment, and the execution of collaborative control logic. The main controller connects to the motor controller, diesel engine ECU, and sensor system via CAN bus communication to achieve high-speed data interaction. The preferred communication baud rate is set to [value missing]. To ensure real-time performance, the motor controller receives commands from the main controller and performs smooth switching between ISG motor modes. Internally, it includes a three-phase inverter bridge and a current sampling circuit. The ISG motor is a permanent magnet synchronous motor, mechanically connected to the diesel engine to directly transmit torque. It can function as both a motor outputting drive torque and a generator outputting load torque. The sensor system includes a temperature sensor, an altitude sensor, and a speed sensor, used to collect ambient temperature data in real time. Altitude and the real-time speed of the diesel engine The data is then transmitted to the main controller via the CAN bus. Preferably, a PT100 platinum resistance thermometer is used for the temperature sensor, a MEMS barometric pressure sensor is used for the altitude sensor, and a magnetoelectric or Hall effect sensor is used for the speed sensor. This architecture fully utilizes the hardware resources of existing ISG systems, and the control method described in this invention can be implemented through software upgrades.

[0029] like Figure 1 As shown, the overall flow of the control method of this invention is as follows: After the system is powered on, it first enters the starting stage, where the ISG motor operates in electric mode, driving the diesel engine crankshaft to rotate. The system determines whether ignition is successful; if not, it restarts; if so, the ISG motor switches to generator mode. Subsequently, the system determines whether an acceleration command has been received; if not, it continues generator operation; if so, it enters the operating condition sensing stage and collects parameters. , , Next, a speed lag risk assessment is performed to determine if auxiliary torque is needed. If not, the generator mode is maintained; if so, the ISG motor smoothly switches from generator mode to electric mode, outputting auxiliary torque to help the diesel engine accelerate. During this process, the system continuously monitors exit conditions, including engine speed. and time If the exit conditions are not met, auxiliary operation continues; if the exit conditions are met, the system smoothly switches back to power generation mode and continues normal power generation operation until the process ends. This flowchart clearly illustrates the complete closed-loop control logic from startup to auxiliary operation and then to power generation recovery.

[0030] The diesel engine ISG system high-altitude low-temperature auxiliary acceleration control method provided by the present invention specifically includes the following steps: The first step is the start-up phase. The ISG motor operates in electric mode, driving the diesel engine crankshaft to rotate. Once the speed reaches and stabilizes at idle, the diesel engine is considered to have successfully ignited. At this point, the ISG motor linearly reduces the starting torque to zero according to a preset slope, smoothly switching from electric mode to generator mode, entering normal generator operation, and the diesel engine enters the stable idle operation phase. This phase primarily addresses the initial ignition issue of the diesel engine, laying the foundation for subsequent operation. During the start-up process, the motor controller employs closed-loop speed control, with the target operating speed set at [value missing]. When the speed fluctuation is less than continued At a certain time, it is determined to be stable.

[0031] The second step is the condition sensing phase. When the driver engages gear and issues a start-up acceleration command, the ambient temperature is simultaneously collected by sensors. Altitude Real-time speed of diesel engine This stage is a prerequisite for intelligent judgment, providing accurate input parameters for subsequent risk assessment through multi-source data fusion. The data collection frequency is set to... That is, each Data is collected once, and a moving average filter is applied to eliminate noise interference.

[0032] The third step is the stagnation risk assessment phase. This is based on the collected ambient temperature data. and altitude A comprehensive scoring method is used to assess whether the diesel engine has a risk of acceleration lag. Altitude and ambient temperature are mapped to risk scores, which are then added together to obtain a comprehensive score. When the comprehensive score is greater than or equal to a preset threshold, the engine is determined to enter the auxiliary acceleration mode; otherwise, it maintains the normal power generation mode.

[0033] The specific scoring rules are as follows, which are based on the physical characteristics of insufficient intake air and deteriorated combustion in diesel engines under high-altitude and low-temperature conditions: For altitude : when At this point, the altitude risk score is 2 points. At this time, air density is significantly reduced, intake air volume is severely insufficient, and diesel engine combustion efficiency drops dramatically.

[0034] when At this point, the altitude risk score is 1 point. Air density is slightly reduced, and air intake is slightly insufficient.

[0035] when At this point, the altitude risk score is 0. The impact of altitude is negligible.

[0036] For ambient temperature : when At this point, the temperature risk score is 2 points. At this time, the engine oil viscosity is extremely high, fuel atomization is extremely poor, frictional resistance is high, and the combustion chamber temperature is low.

[0037] when At this time, the temperature risk score is 1 point. The impact of low temperature is more obvious.

[0038] when At that time, the temperature risk score was 0. The temperature was suitable at that time.

[0039] The altitude score and temperature score are added together to obtain a comprehensive score, and the auxiliary torque level is determined based on the comprehensive score. When the overall score When the time is determined to be an extreme working condition, the auxiliary acceleration mode is activated. When the overall score The time-based assessment indicates a medium-risk operating condition, and the system is set to enter auxiliary acceleration mode. When the overall score When the situation is determined to be a low-risk condition, the auxiliary acceleration mode is activated. When the overall score When the time is determined to be normal operating condition, the auxiliary speed-up mode will not be entered.

[0040] The fourth step is the assisted acceleration phase. When assistance is required, the ISG motor's generating torque gradually decreases to zero at a gentle slope, with the torque change rate controlled within a preset range, achieving a smooth transition from generator mode to electric mode. The ISG motor outputs auxiliary torque. It helps the diesel engine accelerate quickly. The auxiliary torque... The auxiliary torque is determined based on the overall score, with higher scores resulting in greater auxiliary torque.

[0041] The specific formula for calculating the auxiliary torque is as follows, where To provide auxiliary torque, The rated torque of the diesel engine. , , For auxiliary torque coefficient: When the overall score Time-sharing: (1); When the overall score Time-sharing: (2); When the overall score Time-sharing: (3); in, Rated torque of the diesel engine, in units of ; , , As the auxiliary torque coefficient, and satisfying .

[0042] It should be noted that, , , The value is based on the following: First, according to the test data of diesel engine torque loss under high-altitude and low-temperature conditions, the torque gap corresponding to different risk levels is different, and the coefficient is positively correlated with the torque gap; Second, constrained by the rated torque of the ISG motor, this rated torque is approximately [amount missing] of the rated torque of the diesel engine. to ,Pick Within the motor's safe output range; finally, considering battery energy economy, the values ​​are reduced according to risk level. The specific values ​​of the three coefficients are determined through bench calibration, as shown in the embodiment. , , These are typical calibration values.

[0043] Step 5: Exit the judgment phase. Continuously monitor the diesel engine speed. and duration of assistance When the exit conditions are met, the mode switching phase begins. The exit conditions include: rotational speed. Reaching the exit speed threshold And the duration of the assistance Achieve the shortest assistance time Or the duration of the assistance Reaching maximum assist time .

[0044] Among them, the exit speed threshold For the target operating speed of the diesel engine to Times, shortest auxiliary time for to seconds, maximum assist time for to Seconds. Setting the shortest auxiliary time is to prevent frequent switching due to speed fluctuations, while setting the maximum auxiliary time is to prevent motor overheating or battery over-discharge under extreme loads.

[0045] Step 6, Mode Switching Phase. Adjust the auxiliary torque... The torque is gradually reduced in multiple stages, and a preset stabilization time is maintained after each stage of torque reduction. The speed is monitored in real time and maintained at a speed no lower than the stable operating speed. After the auxiliary torque drops to zero, it enters the zero torque range and maintains a preset synchronization time. Then, the generator torque is applied in reverse according to a preset slope to complete the smooth switching of the ISG motor from electric mode to generator mode.

[0046] Among them, the auxiliary torque decrease stage is to Each stage has a torque reduction and a settling time of [time value missing]. to The synchronization time in the zero torque range is to .

[0047] It should be noted that the zero torque range is the transition period for the ISG motor to switch from electric mode to generator mode. It is necessary to wait for the electromagnetic oscillation to decay after the current crosses zero and for the inverter control strategy to switch to the new mode. to The synchronization time is selected based on the magnitude of the auxiliary torque: the larger the auxiliary torque, the longer the decay time of the electromagnetic oscillation after the current crosses zero, and the longer the required synchronization time. In the embodiment, extreme operating conditions... Pick Medium working conditions Pick Light working conditions Pick It is positively correlated with the auxiliary torque. This is the minimum settling time for the current loop response and PWM modulation. This represents the safety margin for electromagnetic oscillation attenuation under maximum torque conditions.

[0048] like Figure 2 As shown in the figure, this diagram illustrates the timing relationships during ISG-assisted acceleration. The horizontal axis represents time. The left side of the vertical axis represents torque, and the right side represents speed. In the legend, the dashed line represents the rotational speed. The solid line segment with an arrowhead represents torque.

[0049] exist At that moment, the system is in power generation mode, the torque is negative, i.e., under load, and the speed slowly increases.

[0050] At the moment of acceleration, the system senses the acceleration command.

[0051] At the moment when assisted acceleration begins, the torque curve rises rapidly from a negative value and crosses... When the point becomes positive, it indicates that the drive is activated, and the rotational speed increases accordingly. It began to rise significantly.

[0052] During the assist phase, the torque is maintained at For extreme operating conditions, the speed It climbs rapidly, with a significantly increased slope.

[0053] At the moment of exiting acceleration, approximately The rotation speed reached Nearby. At this point, the torque begins to decrease in stages, as shown in the diagram, in four steps. This corresponds to the staged torque reduction process during mode switching, the purpose of which is to avoid sudden changes in speed and maintain system smoothness.

[0054] In approximately At that moment, the torque dropped to After a brief period of synchronization within the zero-torque range, the torque becomes negative, and the system re-enters power generation mode, with the speed... Maintain stability .

[0055] The timing diagram clearly demonstrates the smooth transition control logic of this invention, avoiding the impact of sudden speed changes on the system.

[0056] The present invention will be described in detail below with reference to specific embodiments.

[0057] Example 1: High-altitude and low-temperature superimposed working conditions, with a comprehensive score of 3 points, belonging to extreme working conditions. This embodiment provides a method for high-altitude, low-temperature auxiliary acceleration control of a diesel engine ISG system, applicable to high-altitude vehicle equipment, operating in environments with varying altitudes. Ambient temperature .

[0058] The control system includes: the diesel engine itself and the ISG motor, which is a permanent magnet synchronous motor with a rated torque of [missing information]. The system includes an electric motor controller, a diesel engine ECU, a main controller, and a sensor system. The sensor system includes temperature sensors, altitude sensors, and speed sensors.

[0059] The control process is as follows: Step 1: Start-up Phase. The ISG motor drives the diesel engine crankshaft in electric mode, with the speed adjusted according to... The slope increases linearly. The rotational speed was detected to reach [a certain value] seconds later. And if it remains stable, the diesel engine is considered to have ignited successfully. The ISG motor is then activated. The slope decreases, reducing the starting torque to zero, and the system smoothly switches from electric mode to generator mode, entering normal generator operation.

[0060] Step Two: Operating Condition Sensing. After the vehicle engages gear, the driver issues an acceleration command. The system simultaneously collects the ambient temperature. ,altitude Current speed .

[0061] Step 3: Stagnation Risk Assessment. A comprehensive scoring method is used for assessment. Altitude score: 2 points; Temperature score: 2 points; Overall Score: point, point.

[0062] The condition was determined to be an extreme speed lag risk condition, where the diesel engine itself could not accelerate quickly, and it was determined to enter the auxiliary acceleration mode.

[0063] Step 4: Determine the auxiliary torque. (Based on the overall score) Divide, look up the table Calculate the auxiliary torque: ; Step 5: Assisted Speed ​​Increase. The ISG motor generates torque according to a preset slope. Gradually reduce to zero, keeping the rate of torque change within the allowable range; once the generated torque drops to zero, maintain it in the zero torque range. Synchronize; then the auxiliary torque is pressed. The slope gradually increases to This enables a seamless switching from generator mode to electric mode. The ISG motor maintains... The auxiliary torque output helps the diesel engine accelerate.

[0064] Step Six: Exit the judgment. Continuously monitor the rotational speed. and duration of assistance . The rotation speed reached 1 second later Target operating speed, exit speed threshold For the target operating speed times, that is And the duration of the assistance The shortest support time is reached in seconds. Seconds, the normal exit conditions are met.

[0065] Step Seven: Mode Switching. Minutes within seconds The auxiliary torque is gradually reduced, each time decreasing... After each torque reduction, the speed stabilizes. The rotation speed is maintained at The above shows no decrease; once the auxiliary torque drops to zero, it enters the zero torque range and remains there. Synchronize. Then press... The slope reverses the applied torque, and the ISG motor smoothly switches from electric mode back to generator mode, continuing normal power generation operation.

[0066] Example 2: Medium-risk working condition, overall score 2 points This embodiment applies to high-altitude vehicle equipment, operating in environments with varying altitudes. Ambient temperature .

[0067] The control process is as follows: Step 1: The start-up phase is complete, and the ISG motor is operating in generator mode.

[0068] Step Two: Upon receiving the acceleration command, operational status is assessed. Ambient temperature. ,altitude Current speed .

[0069] Step 3: Stagnation Risk Assessment. A comprehensive scoring method is used. Altitude score: 1 point; Temperature score: 1 point; Overall Score: point.

[0070] The condition was determined to be a medium-risk condition for stagnation.

[0071] Step 4: Determine the auxiliary torque. (Based on the overall score) Divide, take Assuming the diesel engine's rated torque... Calculate the auxiliary torque: ; Step 5: Assisted Acceleration and Exit. The ISG motor smoothly switches to electric mode, outputting... Auxiliary torque. After a few seconds, the rotational speed reaches the exit speed threshold, which is the target operating speed. of times, that is And the duration of the assistance The shortest support time is reached in seconds. Seconds, the exit condition is met.

[0072] Step Six: Mode Switching. Assist Torque Division Decreasing in stages, with a steady speed at each stage. ; Synchronization in the zero torque range Reverse loading of power generation torque, smoothly switching back to power generation mode.

[0073] Example 3: Mild risk condition, overall score 1 point This embodiment applies to mountain vehicle equipment, operating in an altitude-limited environment. Ambient temperature .

[0074] The control process is as follows: Step 1: The start-up phase is complete, and the ISG motor is operating in generator mode.

[0075] Step Two: Upon receiving the acceleration command, operational status is assessed. Ambient temperature. ,altitude Current speed .

[0076] Step 3: Stagnation Risk Assessment. A comprehensive scoring method is used. Altitude score: 0 points; Temperature score: 1 point; Overall Score: point.

[0077] The condition was determined to be a low-risk condition for slowdown, and the auxiliary acceleration mode was activated.

[0078] Step 4: Determine the auxiliary torque. (Based on the overall score) Divide, take Assuming the diesel engine's rated torque... Calculate the auxiliary torque: ; Step 5: Assisted acceleration and disengagement. ISG motor output. Auxiliary torque. Due to the relatively small impact of low temperatures, the engine speed increases more rapidly. The rotational speed reaches the exit speed threshold after seconds. And the duration of the assistance The shortest support time is reached in seconds. Seconds, the exit condition is met.

[0079] Step Six: Mode Switching. Assist Torque Division Decreasing in stages, with a steady speed at each stage. Zero torque range synchronization Reverse loading of power generation torque, smoothly switching back to power generation mode.

[0080] Example 4: Under normal operating conditions, the overall score is 0 points, and the auxiliary mode is not entered. This embodiment is applied to a plain area with an ambient temperature of [missing information]. ,altitude .

[0081] The control process is as follows: Step 1: The start-up phase is complete, and the ISG motor is operating in generator mode.

[0082] Step Two: Upon receiving the acceleration command, operational status is assessed. Ambient temperature. ,altitude Current speed .

[0083] Step 3: Stagnation Risk Assessment. A comprehensive scoring method is used. Altitude score: 0 points; Temperature score: 0 points; Overall Score: point.

[0084] If the condition is determined to be normal, maintain the normal power generation mode and do not enter the auxiliary speed-up mode.

[0085] Step 4: The ISG motor continues to operate in generator mode, while the diesel engine relies on its own power to accelerate.

[0086] Example 5: Timeout Exit Scenario This embodiment simulates abnormal situations that occur during the assisted acceleration process to verify the effectiveness of the timeout exit mechanism.

[0087] Setting: Vehicles in a high-altitude region Ambient temperature At this point, the overall score is 3 points.

[0088] The control process is as follows: Steps one through five are the same as in Example 1. The ISG motor enters the auxiliary acceleration mode and outputs auxiliary torque to help the diesel engine accelerate.

[0089] Step Six: Exit Abnormal Situation Assessment. During assisted acceleration, due to a steep road gradient or a sudden increase in driver load, the diesel engine speed may rise slowly. The assisted acceleration will continue until the maximum assisted time is reached. At 1 second, the rotational speed is only At this point, the exit speed threshold has not been reached. The system determines that the auxiliary duration is satisfied. Reaching maximum assist time This condition will result in an execution timeout and exit.

[0090] Step 7: Mode Switching. Following the normal procedure, the auxiliary torque is gradually reduced. After synchronization within the zero torque range, the generator torque is applied in reverse to complete the mode switching. Although the rotational speed did not reach the ideal target, the system's timeout protection mechanism prevented potential safety hazards and energy consumption issues caused by excessively long auxiliary operation.

[0091] Example 6: Software Implementation Architecture Based on Microcontroller Based on the STM32F4 series microcontroller or other equivalent embedded processors, such as DSP and FPGA, the software implementation of this invention can adopt the following architecture, which transforms the above control logic into a specific code execution flow to ensure the real-time performance and reliability of the control method.

[0092] First, define the main state machine enumeration type to manage different operational phases of the system. Define the following states: STATE_IDLE, representing the idle state, used for system power-on initialization; STATE_STARTING, representing the starting state, where the motor drives the crankshaft; STATE_GENERATING, representing the power generation state, used for normal power generation operation; STATE_SENSING, representing the condition sensing state, used for collecting sensor data; and STATE_ASSIST, representing the auxiliary acceleration state, used for outputting auxiliary torque. The state machine transitions between these states based on the current operating conditions, and the main loop period is set to [time value missing]. .

[0093] Secondly, a comprehensive scoring parameter structure, ISG_AssistParamsTypeDef, is defined to store and transfer the data required for the calculation. The structure members include: a float type `temperature`, representing the ambient temperature. The unit is altitude, i.e., altitude The unit is speed, i.e., current rotational speed. The unit is ;assist_torque, i.e., auxiliary torque The unit is alt_score (uint8_t type) is the altitude risk score; temp_score is the temperature risk score; total_score is the overall score; and assist_duration (uint32_t type) is the duration of the assistance function. The unit is .

[0094] Next, configure the threshold and define macro constants for easy modification and calibration: The high altitude threshold ALTITUDE_THRESHOLD_HIGH is set to The unit is ; The mid-altitude threshold ALTITUDE_THRESHOLD_MED is set to The unit is ; The low temperature threshold TEMP_THRESHOLD_LOW is set to 1. The unit is ; The low temperature threshold 2 TEMP_THRESHOLD_MED is set to The unit is ; The exit speed ratio is set to EXIT_SPEED_RATIO. ; The minimum ASSIST_TIME_T1 is set to The unit is ; The maximum ASSIST_TIME_TMAX is set to The unit is ; The torsion reduction stage TORQUE_STEP_COUNT is set to ; The settling time per stage is set to TORQUE_STEP_INTERVAL. The unit is ; Zero torque synchronization time ZERO_TORQUE_SYNC_TIME is set to The unit is .

[0095] Finally, the core control function is implemented, and the specific execution flow is as follows: 1. Comprehensive scoring method evaluation function ISG_CalculateRiskScore: This function accepts a pointer to a parameter structure. First, the altitude score is initialized. and temperature score It is 0.

[0096] Determine altitude: If ,but ;like ,but ;otherwise .

[0097] Determine the temperature: If ,but ;like ,but ;otherwise .

[0098] Calculate the overall score It updates the corresponding fields in the structure and finally returns the value.

[0099] 2. Auxiliary torque calculation function ISG_CalculateAssistTorque: This function receives the overall score. and rated torque .

[0100] Initial coefficients .

[0101] like ,but ,Right now ; like ,but ,Right now ; like ,but ,Right now ; otherwise This indicates that no assistance is provided under normal operating conditions.

[0102] return As auxiliary torque.

[0103] 3. Exit condition judgment function ISG_CheckExitCondition: This function accepts a pointer to a parameter structure.

[0104] Calculate the exit speed .

[0105] Judgment condition 1: If and If it returns 1, it means that a normal exit has been completed.

[0106] Judgment condition 2: If Returning 1 indicates that the timeout has occurred and the program has exited.

[0107] If none of the conditions are met, return 0 to indicate that assistance should continue.

[0108] 4. Mode switching control function ISG_ModeTransition: This function receives auxiliary torque. .

[0109] Calculate the torque reduction step size for each stage. .

[0110] Initialize current torque .

[0111] Execution loop, i.e., graded torque reduction: the number of loops is In each loop, minus Call Motor_SetTorque to set the torque and delay. Milliseconds. This process corresponds to... Figure 2 The stepped torque decreases.

[0112] Zero torque range synchronization: call Motor_SetTorque( ), and delay. Milliseconds. This process waits for the electromagnetic oscillations to decay.

[0113] Reverse loading of generator torque: Call Motor_SetTorque( ), complete the switch.

[0114] It should be noted that those skilled in the art should understand that the specific values ​​given in the above embodiments, such as altitude thresholds, are not necessarily accurate or meaningful. Temperature threshold The time parameters, etc., mentioned above are merely preferred examples. In practical applications, those skilled in the art can adaptively adjust the above thresholds and parameters according to the powertrain characteristics of different vehicle models, the environmental characteristics of different regions, and specific calibration requirements. Any equivalent substitutions or modifications made to the above parameters within the scope of this invention are protected by this invention.

[0115] In summary, compared with the prior art, the present invention has the following significant advantages: First, it effectively solves the acceleration lag problem in high-altitude and low-temperature environments, significantly improving power response performance. This invention breaks through the limitation of traditional ISG systems that only intervene during the starting phase, creatively introducing an electric motor assistance mechanism during the acceleration phase after successful diesel engine ignition. By establishing a comprehensive scoring model based on altitude and ambient temperature, it accurately identifies torque gaps caused by insufficient air intake at high altitudes, increased oil viscosity due to low temperatures, and poor fuel atomization. The system automatically outputs matching auxiliary torque according to the risk level, directly compensating for the diesel engine's power loss. In actual extreme conditions (such as an altitude of 3800m and a temperature of -35℃), this invention can shorten the acceleration process, which originally required more than 20 seconds, to about 6 seconds, reducing acceleration time by more than 70%. This completely solves the pain points of weak acceleration and slow response of diesel engines under harsh conditions, significantly expanding the environmental applicability of diesel engine ISG systems.

[0116] Secondly, it achieves smooth, shock-free switching between modes, ensuring the smoothness of system operation and mechanical lifespan. This invention incorporates rigorous smooth transition logic during the ISG motor's switching from generator mode to electric mode, and during the reverse switching after auxiliary operation ends. Particularly during the auxiliary exit phase, a multi-stage, step-like torque reduction strategy is employed, with a dedicated zero-torque interval synchronization time set after the torque drops to zero. This design fully considers the electromagnetic oscillation attenuation characteristics after the motor current crosses zero and the switching delay of the inverter control strategy. Through an adaptive synchronization wait of 50ms to 200ms, it completely eliminates potential speed jumps and mechanical shocks during reverse torque loading, ensuring the linearity and smoothness of the vehicle's power output and effectively extending the service life of the diesel engine crankshaft and transmission system.

[0117] Third, the control logic is highly intelligent and adaptive, balancing acceleration efficiency and energy economy. This invention abandons blind assistance with fixed parameters and adopts a multi-parameter fusion comprehensive scoring method for intelligent decision-making. Based on the comprehensive score (0 to 4 points), the operating conditions are subdivided into four levels: normal, mild, moderate, and extreme, and different auxiliary torque coefficients are matched accordingly. This on-demand allocation mechanism ensures that only the minimum necessary assistance is provided under mild risk conditions, avoiding excessive energy consumption; while under extreme risk conditions, maximum torque support is provided to ensure the vehicle can safely get out of trouble. At the same time, the system sets dual exit thresholds for the shortest and maximum assistance times, preventing frequent mode switching due to speed fluctuations and avoiding overheating of the motor or over-discharge of the power battery due to excessive assistance time under extreme loads, achieving a perfect balance between power and economy.

[0118] Fourth, it possesses a comprehensive abnormal operating condition protection mechanism, significantly improving the system's robustness and safety. To address unforeseen abnormal situations such as steep gradients on mountainous roads or sudden increases in driver load, this invention incorporates a timeout exit protection mechanism. When the auxiliary operating time reaches the maximum safety threshold (e.g., 8 seconds) and the rotational speed still fails to meet the standard, the system can forcibly determine that the exit conditions are met, automatically reduce torque, and switch back to generator mode. This mechanism effectively prevents the ISG motor from being under high current overload for extended periods, avoiding potential safety hazards and energy waste, and ensuring reliable system operation under abnormal conditions.

[0119] Fifth, it boasts excellent technical compatibility and low engineering implementation costs. The control method of this invention has clear logic and can be fully implemented based on existing diesel engine ISG system hardware architectures (such as main controllers, motor controllers, CAN bus, and conventional sensors). As shown in the microcontroller-based software implementation architecture provided in Example 6, this invention only requires software algorithm upgrades and parameter calibration for deployment, without incurring any additional hardware costs. This decoupled hardware and software design has extremely high technical compatibility and engineering promotion value, facilitating rapid and widespread application in various high-altitude special vehicles and commercial vehicles.

[0120] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are 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 high-altitude and low-temperature auxiliary acceleration control of a diesel engine ISG system, applied to a diesel engine starter-generator system, wherein the diesel engine starter-generator system includes a main controller, an ISG motor, a motor controller, a diesel engine ECU, and a sensor system, characterized in that... The aforementioned method for high-altitude and low-temperature assisted acceleration control of a diesel engine ISG system includes the following steps: Step 1, Start-up phase: The ISG motor operates in electric mode, driving the diesel engine crankshaft to rotate; when the speed reaches the idle speed condition and remains stable, it is considered that the diesel engine has been successfully ignited. The ISG motor linearly reduces the starting torque to zero according to the preset slope, smoothly switching from electric mode to generator mode, and enters normal generator operation. Step 2, Operating Condition Sensing Phase: Upon receiving an acceleration command, the ambient temperature is synchronously collected through the sensor system. Altitude Real-time speed of diesel engine ; Step 3, Stagnation Risk Assessment Stage: Based on the collected ambient temperature data... and altitude A comprehensive scoring method was used to assess whether the diesel engine had a risk of acceleration lag. Altitude and ambient temperature were mapped to risk scores, which were then summed to obtain a comprehensive score. When the comprehensive score... If the system is set to enter auxiliary speed-up mode, it will enter normal power generation mode; otherwise, it will maintain normal power generation mode. Step 4, Assisted Acceleration Phase: When assistance is required, the ISG motor gradually reduces the generating torque to zero at a gentle slope. After the generating torque drops to zero, it enters the zero torque range and maintains synchronization for a preset time. Subsequently, the auxiliary torque is gradually increased at a preset slope until... This enables a seamless switching from power generation mode to electric mode; the ISG motor outputs auxiliary torque. The auxiliary torque helps the diesel engine accelerate quickly; Determined based on the overall score, categorized into different tiers; Step 5, Exit the judgment phase: Continuously monitor the diesel engine speed. and duration of assistance When the exit conditions are met, the mode switching phase begins; the exit conditions include: rotational speed. Reaching the exit speed threshold And the duration of the assistance Achieve the shortest assistance time Or the duration of the auxiliary Reaching maximum assist time ; Step 6, Mode Switching Stage: The auxiliary torque... The torque is gradually reduced in multiple stages, and a preset steady speed time is maintained after each stage of torque reduction. After the auxiliary torque drops to zero, it enters the zero torque range and maintains a preset synchronization time. Then, the generator torque is applied in reverse according to a preset slope to complete the smooth switching of the ISG motor from electric mode to generator mode.

2. The method for high-altitude low-temperature assisted acceleration control of a diesel engine ISG system according to claim 1, characterized in that, In step 3, the specific scoring rules are as follows: For altitude :when When, 2 points are scored; when When, 1 point is awarded; when At that time, 0 points were awarded; Regarding ambient temperature :when When, 2 points are scored; when When, 1 point is awarded; when At that time, 0 points were awarded; The auxiliary torque gear is determined based on the overall score: when the overall score is... The time-sharing process is judged as an extreme working condition; when the overall score is... The timeframe was determined to be a medium-risk working condition; when the overall score... The timeframe was determined to be a low-risk condition; when the overall score... The time-sharing process is considered a normal operating condition.

3. The method for high-altitude low-temperature auxiliary acceleration control of a diesel engine ISG system according to claim 1, characterized in that, In step 4, the auxiliary torque The calculation formula is as follows: When the overall score Time-sharing ; When the overall score Time-sharing ; When the overall score Time-sharing ; in, The rated torque of the diesel engine. , , As the auxiliary torque coefficient, and .

4. The method for high-altitude low-temperature auxiliary acceleration control of a diesel engine ISG system according to claim 3, characterized in that, The auxiliary torque coefficient , , .

5. The method for high-altitude low-temperature auxiliary acceleration control of a diesel engine ISG system according to claim 1, characterized in that, In step 5, the exit speed threshold For the target operating speed of the diesel engine to The shortest auxiliary time is times that of the previous one. for to seconds, the maximum auxiliary time for to Second.

6. The method for high-altitude low-temperature auxiliary acceleration control of a diesel engine ISG system according to claim 1, characterized in that, In step 6, the number of auxiliary torque reduction stages is: to Each stage has a torque reduction and a settling time of [time value missing]. to The synchronization time in the zero torque range is... to .

7. The method for high-altitude low-temperature assisted acceleration control of a diesel engine ISG system according to claim 6, characterized in that, The synchronization time in the zero-torque range is selected based on the magnitude of the auxiliary torque: the larger the auxiliary torque, the longer the required synchronization time; specifically, when the auxiliary torque is... At that time, the synchronization time is taken When the auxiliary torque is At that time, the synchronization time is taken When the auxiliary torque is At that time, the synchronization time is taken .

8. The method for high-altitude low-temperature auxiliary acceleration control of a diesel engine ISG system according to claim 1, characterized in that, In step 1, during the startup process, the motor controller employs closed-loop speed control, and the target operating speed is set to... When the speed fluctuation is less than continued At a certain time, it is determined to be stable.

9. The method for high-altitude low-temperature auxiliary acceleration control of a diesel engine ISG system according to claim 1, characterized in that, The sensor system includes a temperature sensor, an altitude sensor, and a speed sensor, which are used to collect ambient temperature data in real time. Altitude and the real-time speed of the diesel engine The main controller is connected to the motor controller, diesel engine ECU, and sensor system via CAN bus communication.

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