Cooling liquid temperature ultra-high limit fault optimization strategy
By using a multi-state switching strategy to dynamically adjust the coolant temperature limit based on engine operating parameters, the problem of misjudgment and missed judgment in the fault diagnosis of coolant temperature exceeding the limit is solved, and the engine operating condition is accurately identified and safety is ensured.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGXI YUCHAI MASCH CO LTD
- Filing Date
- 2026-02-28
- Publication Date
- 2026-05-12
AI Technical Summary
In the existing technology, the fault diagnosis strategy for coolant temperature exceeding the limit has problems such as high false alarm rate, high risk of false alarm and poor flexibility. It cannot dynamically adjust the threshold according to the engine operating status, resulting in frequent false alarms and potential engine overheating hazards.
A multi-state switch strategy is adopted, which sets the trigger conditions of the multi-state switch according to engine operating parameters (such as real-time load, vehicle speed, fan status and coolant temperature), dynamically adjusts the water temperature limit, and realizes precise linkage between operating condition identification and temperature threshold.
It improves the flexibility and accuracy of fault diagnosis, reduces false alarms, enhances user experience, and ensures engine operating safety.
Smart Images
Figure CN122014397A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to coolant control technology, and more specifically, to a fault optimization strategy for coolant temperature exceeding the upper limit. Background Technology
[0002] In the field of engine control systems, coolant temperature is a core monitoring parameter for ensuring the safe and stable operation of the engine. When the coolant temperature exceeds a safe threshold, the control system needs to trigger an alarm or protection strategy to prevent serious engine failures such as cylinder scoring or bearing seizure due to overheating.
[0003] The current fault diagnosis strategy uses a uniform temperature threshold, which sets fixed alarm and protection thresholds for coolant over-limit faults without distinguishing the actual operating conditions of the engine.
[0004] The reasonable upper limit of coolant temperature varies significantly under different operating conditions: During normal operation, the oncoming airflow generated by vehicle movement enhances heat dissipation, resulting in a lower reasonable upper limit of temperature; during the engine shutdown and warm-up phase, the water pump stops, causing residual heat from the cylinder block to flow back into the coolant, causing the temperature to spike briefly; during idling, there is no wind to assist in cooling, resulting in a higher reasonable upper limit of temperature than during normal operation; under high-load conditions such as climbing hills or getting out of trouble, the engine generates a large amount of heat from fuel combustion, and there may be insufficient fan airflow, requiring a further increase in the reasonable upper limit of temperature; when the fan is not working, the cooling capacity decreases significantly, and the temperature threshold needs to be adapted to special scenarios without forced cooling.
[0005] With the strict implementation of the China VI emission standards and the increasing demands from users for engine reliability and fault diagnosis accuracy, traditional single-threshold diagnostic strategies are no longer sufficient to meet practical application needs.
[0006] The existing technology has the following drawbacks:
[0007] (1) High fault misjudgment rate When a uniform temperature threshold is used, normal temperature spikes under operating conditions such as shutdown reheating and idling may be misjudged as faults, leading to frequent fault alarms, interfering with normal user operation, and increasing the workload of after-sales troubleshooting.
[0008] (2) High risk of missing fault diagnosis Under conditions such as climbing hills, getting out of trouble, and when the fan is not working, the upper limit of the reasonable coolant temperature is higher than the conventional threshold. If a fixed standard is still used, there will be situations where the actual temperature is close to the danger value but the system does not trigger an alarm, which poses a risk of engine overheating and damage.
[0009] (3) Poor flexibility of diagnostic strategies Existing strategies cannot dynamically adjust thresholds based on engine operating status, have weak adaptability, and are difficult to meet the multi-scenario, high-precision fault diagnosis requirements of China VI controllers. Summary of the Invention
[0010] The technical problem to be solved by the present invention is to provide an optimized strategy for coolant temperature exceeding the limit fault, which addresses the shortcomings of the existing technology. The existing fault diagnosis strategy based on a single temperature threshold has technical problems such as high fault misjudgment rate, high risk of fault omission and poor flexibility.
[0011] The coolant temperature exceeding the limit fault optimization strategy of the present invention includes: collecting engine operating parameters; setting trigger conditions for a multi-state switch according to the engine operating parameters; setting the switch state of the multi-state switch to the open state when the trigger conditions of the multi-state switch meet the preset opening requirements; setting the switch state of the multi-state switch to the closed state when the trigger conditions of the multi-state switch do not meet the opening requirements; and setting a coolant temperature limit according to the switch state of the multi-state switch.
[0012] As a further improvement, the engine operating parameters include real-time engine load, real-time vehicle speed, engine operating status, fan operating status, and coolant temperature; and vehicle speed limit and fan start-up temperature threshold are set. The triggering conditions include a first triggering condition, a second triggering condition, and a third triggering condition, wherein the first triggering condition is whether the engine is in a stopped state. The real-time vehicle speed is compared with the vehicle speed limit value. The second triggering condition is whether the real-time vehicle speed is less than the vehicle speed limit value and whether the vehicle speed sensor is in a fault state. The coolant temperature is compared with the fan start-up temperature threshold, and the third trigger condition is whether the coolant temperature is greater than or equal to the fan start-up temperature threshold. The engine real-time load is compared with the engine real-time load lower limit. The fourth trigger condition is whether the real-time vehicle speed is less than the vehicle speed limit, whether the vehicle speed sensor is in a fault state, and whether the engine real-time load is greater than the engine real-time load lower limit.
[0013] Furthermore, the opening requirements include a first opening requirement, a second opening requirement, a third opening requirement, and a fourth opening requirement. The first requirement for starting the engine is that the engine is in a stopped state. The second activation requirement is that the real-time vehicle speed is less than the vehicle speed limit and the vehicle speed sensor is in a fault-free state; The third activation requirement is that the coolant temperature is greater than or equal to the fan start-up temperature threshold. The fourth activation requirement is that the real-time vehicle speed is less than the vehicle speed limit, the vehicle speed sensor is in a fault state, and the real-time engine load is greater than the lower limit of the real-time engine load. When the first, second, third, or fourth opening requirement is met, the switch state of the multi-state switch is set to the open state; otherwise, the switch state of the multi-state switch is set to the closed state.
[0014] Furthermore, the method for selecting the water temperature limit based on the switch status is as follows: The water temperature limits include a first water temperature limit, a second water temperature limit, a third water temperature limit, a fourth water temperature limit, a fifth water temperature limit, and a sixth water temperature limit; When the switch of the multi-position switch is in the open state, the second water temperature limit, the fourth water temperature limit, and the sixth water temperature limit are selected. When the switch of the multi-position switch is in the closed state, the first water temperature limit, the third water temperature limit, and the fifth water temperature limit are selected.
[0015] Furthermore, a fault alarm is triggered when the coolant temperature is greater than or equal to the fan start-up temperature threshold; the fault alarm is deactivated when the coolant temperature is less than the fan start-up temperature threshold. Beneficial effects The advantages of this invention are: This invention determines the on / off state of a multi-state switch based on collected engine operating parameters, and sets a coolant temperature limit based on the on / off state. This achieves precise linkage between operating condition identification and temperature threshold, solving the technical challenge of adapting a single threshold to multiple operating conditions, improving the accuracy of engine operating condition determination, enhancing the flexibility and precision of fault diagnosis, improving user experience, and ensuring engine operating safety. Attached Figure Description
[0016] Figure 1 This is a flowchart of the coolant temperature exceeding the high limit fault optimization strategy of the present invention. Detailed Implementation
[0017] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.
[0018] See Figure 1 The present invention provides a fault optimization strategy for coolant temperature exceeding the upper limit, the strategy comprising, Step 1: Collect engine operating parameters. Engine operating parameters include real-time engine load, real-time vehicle speed, engine operating status, fan operating status, and coolant temperature; set vehicle speed limits and fan start-up temperature thresholds.
[0019] Step 2: Determine the switching state of the multi-state switch based on the engine operating parameters.
[0020] The triggering conditions of the multi-state switch are set according to the engine operating parameters. When the triggering conditions of the multi-state switch meet the preset opening requirements, the switch state of the multi-state switch is set to the open state; when the triggering conditions of the multi-state switch do not meet the opening requirements, the switch state of the multi-state switch is set to the closed state.
[0021] The triggering conditions include a first triggering condition, a second triggering condition, and a third triggering condition. The first triggering condition is whether the engine is in a stopped state.
[0022] The real-time vehicle speed is compared with the speed limit value. The second trigger condition is whether the real-time vehicle speed is less than the speed limit value and whether the vehicle speed sensor is in a faulty state.
[0023] The system compares the coolant temperature with the fan start-up temperature threshold. A third trigger condition is whether the coolant temperature is greater than or equal to the fan start-up temperature threshold. When the coolant temperature is greater than or equal to the fan start-up temperature threshold, a fault alarm is triggered; when the coolant temperature is less than the fan start-up temperature threshold, the fault alarm is deactivated. An appropriate temperature threshold is set for the fan's inactivity to avoid normal temperature fluctuations being misinterpreted as faults, reducing invalid alarms and improving the user experience.
[0024] The engine real-time load is compared with the engine real-time load lower limit. The fourth trigger condition is whether the real-time vehicle speed is less than the vehicle speed limit, whether the vehicle speed sensor is in a fault state, and whether the engine real-time load is greater than the engine real-time load lower limit.
[0025] The opening requirements include a first opening requirement, a second opening requirement, a third opening requirement, and a fourth opening requirement. The first requirement for starting the engine is that the engine is in a stopped state and the engine operating condition is identified as a stopped reheating condition.
[0026] The second activation requirement is that the real-time vehicle speed is less than the vehicle speed limit and the vehicle speed sensor is functioning correctly. It also identifies the engine operating condition as idling.
[0027] The third activation requirement is that the coolant temperature is greater than or equal to the fan start-up temperature threshold. The system also identifies the engine operating condition as a fan failure condition.
[0028] The fourth activation requirement is that the real-time vehicle speed is less than the speed limit, the speed sensor is functioning correctly, and the real-time engine load is greater than the lower limit of the real-time engine load. The engine operating condition is then identified as an obstacle-avoiding and hill-climbing condition.
[0029] When the first, second, third, or fourth opening requirement is met, the switch state of the multi-state switch is set to the open state; otherwise, the switch state of the multi-state switch is set to the closed state.
[0030] By integrating multi-dimensional parameters such as engine shutdown status, vehicle speed signal, fan operating status, real-time engine load, and water temperature, a working condition identification system is constructed that covers scenarios such as engine shutdown and reheating, idling, fan not working, climbing, and getting out of trouble, ensuring the accuracy of working condition judgment.
[0031] Step 3: Set the water temperature limit based on the on / off state of the multi-state switch. The method for selecting the water temperature limit based on the on / off state is as follows: The water temperature limits include the first water temperature limit, the second water temperature limit, the third water temperature limit, the fourth water temperature limit, the fifth water temperature limit, and the sixth water temperature limit.
[0032] When the switch of the multi-position switch is in the open state, the second water temperature limit, the fourth water temperature limit, and the sixth water temperature limit are selected.
[0033] When the multi-position switch is in the off state, the first, third, and fifth water temperature limits are selected. The first and second water temperature limits correspond to the two limits for a level one overheating fault; in this embodiment, the first water temperature limit is 118℃ and the second water temperature limit is 120℃. The third and fourth water temperature limits correspond to the two limits for a level two overheating fault; in this embodiment, the third water temperature limit is 114℃ and the fourth water temperature limit is 116℃. The fifth and sixth water temperature limits correspond to the two limits for a level three overheating fault; in this embodiment, the fifth water temperature limit is 110℃ and the sixth water temperature limit is 112℃.
[0034] By switching between switches, the threshold can be dynamically adjusted under different operating conditions, improving the flexibility and accuracy of fault diagnosis. A multi-state switch is used to define the triggering conditions for different operating conditions, achieving precise linkage between operating condition identification and temperature threshold, thus solving the technical challenge of adapting a single threshold to multiple operating conditions.
[0035] The design of the multi-state switch makes the operating condition recognition logic scalable. More operating conditions can be recognized and thresholds can be configured by adding new switch states to adapt to the needs of different engine models.
[0036] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.
Claims
1. A fault optimization strategy for coolant temperature exceeding the upper limit, characterized in that: The strategy includes collecting engine operating parameters, setting trigger conditions for a multi-state switch based on the engine operating parameters, setting the multi-state switch to the on state when the trigger conditions meet preset opening requirements, setting the multi-state switch to the off state when the trigger conditions do not meet the opening requirements, and setting a water temperature limit based on the on / off state of the multi-state switch.
2. The coolant temperature exceeding the upper limit fault optimization strategy according to claim 1, characterized in that, The engine operating parameters include real-time engine load, real-time vehicle speed, engine operating status, fan operating status, and coolant temperature; vehicle speed limit and fan start-up temperature threshold are set. The triggering conditions include a first triggering condition, a second triggering condition, and a third triggering condition, wherein the first triggering condition is whether the engine is in a stopped state. The real-time vehicle speed is compared with the vehicle speed limit value. The second triggering condition is whether the real-time vehicle speed is less than the vehicle speed limit value and whether the vehicle speed sensor is in a fault state. The coolant temperature is compared with the fan start-up temperature threshold, and the third trigger condition is whether the coolant temperature is greater than or equal to the fan start-up temperature threshold and whether the fan is not working. The engine real-time load is compared with the engine real-time load lower limit. The fourth trigger condition is whether the real-time vehicle speed is less than the vehicle speed limit, whether the vehicle speed sensor is in a fault state, and whether the engine real-time load is greater than the engine real-time load lower limit.
3. The coolant temperature exceeding the upper limit fault optimization strategy according to claim 2, characterized in that, The opening requirements include a first opening requirement, a second opening requirement, a third opening requirement, and a fourth opening requirement. The first requirement for starting the engine is that the engine is in a stopped state. The second activation requirement is that the real-time vehicle speed is less than the vehicle speed limit and the vehicle speed sensor is in a fault-free state; The third activation requirement is that the coolant temperature is greater than or equal to the fan start-up temperature threshold and the fan is not working. The fourth activation requirement is that the real-time vehicle speed is less than the vehicle speed limit, the vehicle speed sensor is in a fault state, and the real-time engine load is greater than the lower limit of the real-time engine load. When the first, second, third, or fourth opening requirement is met, the switch state of the multi-state switch is set to the open state; otherwise, the switch state of the multi-state switch is set to the closed state.
4. The coolant temperature exceeding the upper limit fault optimization strategy according to claim 3, characterized in that, The method for selecting the water temperature limit based on the switch status is as follows: The water temperature limits include a first water temperature limit, a second water temperature limit, a third water temperature limit, a fourth water temperature limit, a fifth water temperature limit, and a sixth water temperature limit; When the switch of the multi-position switch is in the open state, the second water temperature limit, the fourth water temperature limit, and the sixth water temperature limit are selected. When the switch of the multi-position switch is in the closed state, the first water temperature limit, the third water temperature limit, and the fifth water temperature limit are selected.
5. The coolant temperature exceeding the upper limit fault optimization strategy according to claim 2, characterized in that, A fault alarm is triggered when the coolant temperature is greater than or equal to the fan start-up temperature threshold; the fault alarm is deactivated when the coolant temperature is less than the fan start-up temperature threshold.