Low-temperature control method and system for off-road vehicle front-end wheel train high-voltage power generation system and storage medium

Abstract

The invention discloses a low-temperature control method for a high-voltage power generation system of a front-end wheel train of an off-road vehicle, and the method comprises a low-temperature compensation control method: after the whole vehicle is powered on, obtaining an idle running time threshold value of an engine according to a water temperature checking curve, and enabling the high-voltage power generation system when the idle running time of the engine exceeds the idle running time threshold value of the engine; the power limit control method comprises the following steps: after the high-voltage power generation system is enabled, reference is carried out according to the battery SOC, the water temperature value, the power generator limit value power and the power generator external characteristic power to set a power generation power threshold value; the rotating speed active increasing control method comprises the steps that in the parking state, the target rotating speed of an engine is determined based on voltage parameters or load power, and rotating speed active increasing is executed; the low-temperature cold start idling stability and NVH are effectively achieved, the stability of a power generation system is guaranteed, the driving habit of a driver is not affected, operation under other working conditions is not affected, and engine control and power generation system control are integrated.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage power generation systems for off-road vehicles, specifically relating to a low-temperature control method for a high-voltage power generation system in the front wheel system of an off-road vehicle. Background Technology

[0002] With the popularization and promotion of electrification, the number of onboard devices is increasing. The low-voltage power supply originally provided by off-road vehicles can no longer meet the needs of electrification retrofitting. Their power demand is developing towards high voltage and high power. The front wheel system high-voltage power generation system adopts a P0 hybrid structure, which has a small footprint in the chassis and is lightweight. At the same time, there is no need to switch between driving and parking power generation, which has very obvious advantages. Off-road vehicle application scenarios are complex and extremely low temperature operating conditions need to be considered. Although off-road vehicles usually use intake air preheating and on-board liquid heating systems to meet the requirements of cold start in low temperature conditions, the presence of the high-voltage power generation system will increase the load and increase the difficulty of engine starting. Furthermore, immediately activating the high-voltage power generation system and loading a high-power electrical load when the engine is cold can cause engine speed to vibrate or even stall, which is detrimental to system stability. Therefore, it is necessary to enable the high-voltage power generation system at low temperatures, and corresponding low temperature compensation control strategies and power limiting strategies are required.

[0003] After the engine starts and enters the parking state, the engine is in a low idle speed mode. The power generation system relies on the limited energy provided by the engine. When the electrical load consumption exceeds the maximum energy that the generator can provide, the power battery system will continue to discharge. Therefore, a corresponding active speed increase compensation strategy is required.

[0004] Increasing the engine speed while the vehicle is parked may affect gear shifting and prevent the vehicle from entering driving mode. Therefore, a corresponding driving priority compensation strategy is required. Summary of the Invention

[0005] To address the problems or shortcomings in existing technologies, such as the lack of sophisticated control strategies for the high-voltage power generation system of the front wheel system in off-road vehicles at low temperatures.

[0006] This invention provides a method for cryogenic control of a high-voltage power generation system in the front wheel system of an off-road vehicle, comprising: Low temperature compensation control method: After the vehicle is powered on, the high-voltage power generation control module obtains the current water temperature based on the coolant temperature sensor, and obtains the engine idling time threshold based on the water temperature curve. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system can be enabled. Power limiting control method: After the high-voltage power generation system is enabled, the power generation threshold is set with reference based on the battery SOC, water temperature, generator limit power, and generator external characteristic power. Active speed increase control method: In the parked state, when the load has no feedback, the target engine speed is determined based on the voltage parameters and active speed increase is executed; when the load has feedback, the target engine speed is determined based on the load power and active speed increase is executed; the speed switching is processed by transition.

[0007] Furthermore, the specific method of low-temperature compensation control includes: after the vehicle is powered on, the high-voltage power generation control module controls the high-voltage power generation system to apply low-voltage electricity. After a self-test without serious faults, high-voltage power is applied. The high-voltage power generation control module obtains the current coolant temperature based on its built-in coolant temperature sensor, and obtains the engine idling time threshold based on the coolant temperature curve. After the engine intake air preheating and the on-board liquid heating system operate according to the design logic, the engine is started. The engine speed is obtained based on the speed sensor. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system can be enabled.

[0008] Furthermore, the power limiting control method includes a method for setting a power generation threshold based on battery SOC, water temperature, generator limit power, and generator external characteristic power. This involves obtaining the SOC value from messages sent via the battery CAN bus and the current water temperature from the built-in coolant temperature sensor. When the high-voltage generator system is enabled, if the obtained water temperature is below a certain threshold and the battery SOC is below a certain threshold, the power generation of the high-voltage generator system is limited by the limit power, and the battery is heated using PTC or charged with relatively low power to ensure the operational stability of the engine and generator system. The limit power of the high-voltage generator system is obtained by looking up the generator speed in a table. When the obtained water temperature is above a certain threshold or the battery SOC is above a certain threshold, the power generation of the high-voltage generator system is limited by the generator external characteristic power, and it outputs a larger power output. The generator external characteristic power of the high-voltage generator system is obtained by looking up the generator speed in a table.

[0009] Furthermore, the method for determining the engine target speed based on voltage parameters and actively increasing the speed when the load has no feedback is as follows: when the load power has no feedback, the high-voltage power generation control module obtains the current voltage through the message sent by the battery CAN bus, obtains the control voltage target according to the high-voltage power generation system design input, obtains the filtered voltage according to the current voltage and the filtering coefficient, and obtains the engine target speed according to the difference between the filtered voltage and the control voltage target, as well as the difference confirmation time, thereby realizing the active speed increase compensation strategy.

[0010] Furthermore, the method of determining the engine target speed based on the load power and actively increasing the speed when the load has feedback is as follows: when the load power has feedback, the high-voltage generator control module obtains the load power through the message sent by the load CAN bus. When the load power exceeds the generator's external characteristic power and continues for a certain period of time, the speed is actively increased, and the engine target speed is obtained by looking up a table based on the load power.

[0011] Furthermore, the method for the transition processing of the speed switching is as follows: when the engine switches from the current speed to the target speed, it needs to go through RAMP processing to take into account the smoothness and NVH during the switching of operating conditions.

[0012] Furthermore, it also includes a driving priority control method: when the parking speed is increased, after detecting that the driving braking state has lasted for a preset time, the speed increase is discontinued and the idle speed is restored.

[0013] Furthermore, the vehicle braking status is obtained through a vehicle braking hardwire signal.

[0014] As another aspect of the present invention, a cryogenic control system for a high-voltage power generation system of the front wheel system of an off-road vehicle is also disclosed, comprising: Low temperature compensation control device: After the vehicle is powered on, the high-voltage power generation control module obtains the current water temperature based on the coolant temperature sensor, and obtains the engine idling time threshold based on the water temperature curve. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system can be enabled. Power limiting control device: used to set the power generation threshold based on battery SOC, water temperature, generator limit power, and generator external characteristic power after the high-voltage power generation system is enabled; Active speed boost control device: Used in parked mode, when the load has no feedback, it determines the target engine speed based on voltage parameters and performs active speed boost; when the load has feedback, it determines the target engine speed based on load power and performs active speed boost; speed switching is processed by transition; The driving priority control device is used to disengage the speed increase and restore the idle speed after detecting the driving braking state for a preset time when the parking speed is increased.

[0015] As another aspect of the present invention, a storage medium is also provided, the storage medium storing a computer program that, when executed by a processor, implements the above-described low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle.

[0016] Compared with the prior art, the present invention has the following advantages: (1) The low temperature control method of the high voltage power generation system of the front wheel system of the off-road vehicle of the present invention controls the high voltage power generation system of the front wheel system at low temperature, designs a low temperature compensation control strategy and a power limiting strategy, and effectively solves the low temperature cold start idling stability and NVH.

[0017] (2) The low-temperature control method of the high-voltage power generation system of the front wheel system of the off-road vehicle of the present invention has an active speed increase function, which improves the phenomenon that the generator program cannot perform PID closed-loop control when the high power load continuously exceeds the external characteristic power of the generator, and the high-voltage power generation system continues to drop voltage, thus ensuring the stability of the power generation system.

[0018] (3) The low temperature control method of the high voltage power generation system of the front wheel system of the off-road vehicle of the present invention, through the driving priority compensation strategy, does not affect the overall vehicle power performance, does not affect the driver's driving habits, and does not affect the operation of other working conditions; the high voltage power generation control module is integrated in the engine controller hardware, without adding additional controller hardware, realizing the combination of engine control and power generation system control. Attached Figure Description

[0019] Figure 1 This is a flowchart of low-temperature compensation control and power limiting control. Figure 2 This is the flowchart of the active speed increase control. Figure 3 This is a flowchart of the traffic priority strategy. Figure 4 This is a system structure diagram of a preferred embodiment of the present invention; Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] The cryogenic control of the high-voltage power generation system in the front wheel system of off-road vehicles faces the following requirements: The control of the front-end wheel system high-voltage power generation system at low temperatures needs to take into account both the cold start of the engine and the idling stability and NVH after start-up.

[0022] When the vehicle is parked, the engine speed is fixed, the power generation capacity of the high-voltage power generation system is limited, the battery system will continue to discharge, and the power generation system cannot work in a stable voltage manner. Therefore, a corresponding active speed increase strategy is required.

[0023] When the engine speed is increased while the vehicle is parked, gear shifting will be impossible when switching between parking and driving, affecting driving. A driving priority compensation strategy is required to ensure the driver's driving needs. When the vehicle enters the idle speed increase state, pressing the brake pedal will deactivate the active speed increase function, and the engine will return to idle speed, allowing gear shifting and driving.

[0024] To address the aforementioned needs, embodiments of the present invention relate to a cryogenic control method for a high-voltage power generation system in the front wheel system of an off-road vehicle, specifically including: (1) Introduce a low temperature compensation control strategy Please refer to Figure 1 After the vehicle is powered on, the high-voltage power generation control module controls the high-voltage power generation system to apply low-voltage electricity. After a self-test confirms no serious faults, high-voltage power is applied. The high-voltage power generation control module obtains the current coolant temperature using its built-in coolant temperature sensor and uses a temperature curve to determine the engine idling time threshold. After the engine intake air preheating and onboard liquid heating system operate according to the design logic, the engine is started. The engine speed is obtained from the speed sensor. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system is activated.

[0025] (2) Introduce power limiting strategy After the high-voltage generator system is enabled, directly applying high power at low temperatures can cause engine speed fluctuations or even stalling. Simultaneously, due to the significantly limited battery discharge performance at low temperatures, high power application can also lead to voltage stabilization issues. Therefore, it is necessary to limit the power output of the high-voltage generator system. The power output threshold needs to be set based on the battery SOC, coolant temperature, generator limit power, and generator external characteristic power. Specifically: The SOC value is obtained from the messages sent by the battery CAN bus, and the current coolant temperature is obtained from the built-in coolant temperature sensor. When the high-voltage generator system is enabled, if the obtained coolant temperature and battery SOC are both below a certain threshold, the power output of the high-voltage generator system is limited by the limit power, using relatively low power to heat the battery with PTC or charge the battery, ensuring the operational stability of the engine and generator system. The limit power of the high-voltage generator system is obtained by looking up the generator speed in a table. When the obtained coolant temperature or battery SOC is above a certain threshold, the power output of the high-voltage generator system is limited by the generator external characteristic power, outputting a larger power. The generator external characteristic power of the high-voltage generator system is obtained by looking up the generator speed in a table.

[0026] (3) Active speed increase strategy Please refer to Figure 2In the parked state, with the engine speed fixed, to prevent the generator program from failing to perform PID closed-loop control and the high-voltage power generation system from continuously dropping voltage when the high-power load continuously exceeds the generator's external characteristic power, the following design is implemented to ensure the stability of the power generation system, considering two operating conditions: When the load power is not fed back, the high-voltage power generation control module obtains the current voltage through the message sent by the battery CAN bus, obtains the control voltage target according to the high-voltage power generation system design input, obtains the filtered voltage according to the current voltage and the filtering coefficient, and obtains the engine target speed according to the difference between the filtered voltage and the control voltage target, as well as the difference confirmation time, to realize the active speed increase compensation strategy.

[0027] When the load power has feedback, the high-voltage generator control module obtains the load power through the message sent by the load CAN bus. When the load power exceeds the generator's external characteristic power and continues for a certain period of time, the engine speed is actively increased, and the engine target speed is obtained by looking up a table based on the load power.

[0028] Meanwhile, when the engine switches from the current speed to the target speed, it needs to go through RAMP processing to take into account both the smoothness and NVH during the switching of operating conditions.

[0029] (4) Traffic priority strategy Please refer to Figure 3 After the engine speed is increased while the vehicle is parked, the high-voltage power generation control needs to take into account the driver's driving needs. The high-voltage power generation control module obtains the driving braking status through the driving braking hard wire signal. When it detects that the vehicle is in the driving braking state for a certain period of time, it exits the active speed increase strategy and the vehicle returns to the idling state. The driver can then shift gears and start driving to achieve the driving priority intention.

[0030] The high-voltage power generation control module uses signals from the system's built-in coolant level, service brake hard-wired signal, and engine speed signal. It also collects signals from the CAN bus, including the fault status of high-voltage components, battery SOC, battery voltage, and load power, to control the high-voltage power generation system. By introducing low-temperature compensation and power limiting strategies, it determines the timing and power limit for enabling the power generation system after engine start. Simultaneously, at idle, it calculates the difference between battery voltage and the target control voltage, or the difference between load power and the generator's external characteristic power, to obtain the target engine speed, while also prioritizing the driver's driving needs.

[0031] Please refer to Figure 4 In some preferred embodiments, a cryogenic control system for a high-voltage power generation system of the front wheel system of an off-road vehicle is also disclosed, comprising: Low temperature compensation control device: After the vehicle is powered on, the high-voltage power generation control module obtains the current water temperature based on the coolant temperature sensor, and obtains the engine idling time threshold based on the water temperature curve. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system can be enabled. Power limiting control device: used to set the power generation threshold based on battery SOC, water temperature, generator limit power, and generator external characteristic power after the high-voltage power generation system is enabled; Active speed boost control device: Used in parked mode, when the load has no feedback, it determines the target engine speed based on voltage parameters and performs active speed boost; when the load has feedback, it determines the target engine speed based on load power and performs active speed boost; speed switching is processed by transition; The driving priority control device is used to disengage the speed increase and restore the idle speed after detecting the driving braking state for a preset time when the parking speed is increased.

[0032] In some preferred embodiments, a storage medium is also involved, which stores a computer program that, when executed by a processor, implements the above-described low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle.

[0033] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for cryogenic control of a high-voltage power generation system in the front wheel system of an off-road vehicle, characterized in that, include: Low temperature compensation control method: After the vehicle is powered on, the high-voltage power generation control module obtains the current water temperature based on the coolant temperature sensor, and obtains the engine idling time threshold based on the water temperature curve. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system is enabled. Power limiting control method: After the high-voltage power generation system is enabled, the power generation threshold is set with reference based on the battery SOC, water temperature, generator limit power, and generator external characteristic power. Active speed increase control method: In the parked state, when the load has no feedback, the target engine speed is determined based on the voltage parameters and active speed increase is executed; when the load has feedback, the target engine speed is determined based on the load power and active speed increase is executed. The speed switching is handled by a transition process.

2. The low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle according to claim 1, characterized in that, The specific methods of the low-temperature compensation control method include: after the vehicle is powered on, the high-voltage power generation control module controls the high-voltage power generation system to apply low-voltage electricity. After a self-test without serious faults, high-voltage power is applied. The high-voltage power generation control module obtains the current water temperature based on its built-in coolant temperature sensor, and obtains the engine idling time threshold based on the water temperature curve. After the engine intake air preheating and the on-board liquid heating system work according to the design logic, the engine is started. The engine speed is obtained based on the speed sensor. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system can be enabled.

3. The low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle according to claim 1, characterized in that, The power limiting control method includes a method for setting a power generation threshold based on battery SOC, water temperature, generator limit power, and generator external characteristic power. This involves obtaining the SOC value from messages sent via the battery CAN bus and the current water temperature from the built-in coolant temperature sensor. When the high-voltage generator system is enabled, if the obtained water temperature is below a certain threshold and the battery SOC is below a certain threshold, the power generation of the high-voltage generator system is limited by the limit power, using relatively low power to heat the battery with PTC or charge the battery, ensuring the operational stability of the engine and generator system. The limit power of the high-voltage generator system is obtained by looking up the generator speed in a table. When the obtained water temperature is above a certain threshold or the battery SOC is above a certain threshold, the power generation of the high-voltage generator system is limited by the generator external characteristic power, outputting a larger power output. The generator external characteristic power of the high-voltage generator system is obtained by looking up the generator speed in a table.

4. The low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle according to claim 1, characterized in that, The method for determining the engine target speed and actively increasing the speed based on voltage parameters when the load has no feedback is as follows: When the load power has no feedback, the high-voltage power generation control module obtains the current voltage through the message sent by the battery CAN bus, obtains the control voltage target according to the high-voltage power generation system design input, obtains the filtered voltage according to the current voltage and the filtering coefficient, and obtains the engine target speed according to the difference between the filtered voltage and the control voltage target, as well as the difference confirmation time, thereby realizing the active speed increase compensation strategy.

5. The low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle according to claim 1, characterized in that, The method for determining the engine target speed based on the load power and actively increasing the speed when the load has feedback is as follows: When the load power has feedback, the high-voltage generator control module obtains the load power through the message sent by the load CAN bus. When the load power exceeds the generator's external characteristic power and continues for a certain period of time, the speed is actively increased, and the engine target speed is obtained by looking up a table based on the load power.

6. The low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle according to claim 1, characterized in that, The method for transition processing during speed switching is as follows: when the engine switches from the current speed to the target speed, it needs to go through RAMP processing to take into account both the smoothness and NVH during the switching of operating conditions.

7. The low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle according to claim 1, characterized in that, It also includes a driving priority control method: when the parking speed is increased, after detecting that the driving braking state has lasted for a preset time, the speed increase is stopped and the idle speed is restored.

8. The low-temperature control method for the high-voltage power generation system of the front wheel system of an off-road vehicle according to claim 7, characterized in that, The vehicle braking status is obtained through the vehicle braking hardwire signal.

9. A cryogenic control system for a high-voltage power generation system in the front wheel system of an off-road vehicle, characterized in that, include: Low temperature compensation control device: After the vehicle is powered on, the high-voltage power generation control module obtains the current water temperature based on the coolant temperature sensor, and obtains the engine idling time threshold based on the water temperature curve. When the engine idling time exceeds the engine idling time threshold, the high-voltage power generation system can be enabled. Power limiting control device: used to set the power generation threshold based on battery SOC, water temperature, generator limit power, and generator external characteristic power after the high-voltage power generation system is enabled; Active speed boost control device: When the vehicle is parked and the load has no feedback, it determines the target engine speed based on voltage parameters and performs active speed boost; when the load has feedback, it determines the target engine speed based on load power and performs active speed boost. Speed ​​switching is processed through a transition; The driving priority control device is used to stop increasing the speed and restore the idle speed after detecting that the driving braking state has been in effect for a preset time when the parking speed is increased.

10. A storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 8.

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