Dynamic Coolant Temperature Threshold for Engine Torque Control
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Solution Overview
Problem
Current anti-boiling strategies for heat transfer liquids in vehicle cooling systems either fail to effectively limit temperature rises below the boiling point without penalizing vehicle performance or incur excessive costs in upgrading cooling equipment, leading to reduced engine component lifespan due to high thermal loads.
Innovation Solution
A method that limits engine torque based on predetermined maximum coolant temperature, instantaneous coolant temperature, and vehicle speed, considering engine power, torque, or thermal flux to prevent boiling, while maintaining driving performance by adjusting torque limitations dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the maximum temperature threshold is set at 118°C to prevent boiling, then the heat transfer fluid is protected from boiling, but the engine torque is excessively limited even in situations where boiling risk is low
Solution Approach 1:
The patent applies dynamics by making the temperature threshold dynamic rather than fixed. The threshold adapts in real-time based on multiple factors including heat transfer fluid flow rate, engine power, and ambient temperature. When flow rate is high and cooling capacity is sufficient, the threshold can be raised above 118°C, allowing higher torque. When conditions indicate boiling risk, the threshold lowers to 118°C or below. This dynamic adjustment resolves the contradiction by preventing boiling while avoiding unnecessary torque limitation.
Solution Approach 2:
The patent changes the parameter of temperature threshold from a fixed value to a variable that depends on operating conditions. The control unit calculates an adapted maximum temperature threshold based on real-time parameters such as coolant flow rate, engine power output, and ambient temperature. This parameter change allows the system to maintain boiling prevention (reliability) while optimizing torque availability (productivity) by raising the threshold when cooling capacity is sufficient.
2Reliability
If the maximum temperature threshold is lowered below 118°C to provide earlier protection, then boiling prevention is improved, but vehicle performance is significantly reduced even in safe operating conditions
Solution Approach 1:
The system uses dynamic threshold adjustment based on real-time cooling capacity assessment. When the control unit determines that the cooling system has sufficient capacity (high flow rate, adequate ambient temperature), it raises the threshold above 118°C, allowing the engine to operate at higher torque without risk of boiling. The threshold only lowers to earlier values when actual thermal conditions warrant it, thus providing early protection only when necessary and maintaining performance when safe.
Solution Approach 2:
The patent implements preliminary action by assessing cooling capacity in advance and proactively adjusting the temperature threshold accordingly. Before the engine reaches critical temperatures, the control unit evaluates current cooling conditions and sets an appropriate threshold. This preliminary assessment allows the system to permit higher temperatures (and thus higher torque) when cooling capacity is sufficient, while preparing to lower the threshold if conditions deteriorate, thereby avoiding unnecessary performance reduction.
3Device complexity
If a fixed temperature threshold of 118°C is used, then the control system is simple to implement, but it cannot adapt to varying cooling capacities and operating conditions
Solution Approach 1:
The patent changes the temperature threshold parameter from fixed to variable based on operating conditions. The control unit calculates an adapted maximum temperature threshold using inputs such as heat transfer fluid flow rate, engine power, and ambient temperature. This parameter change enables the system to adapt to varying cooling capacities while maintaining reasonable complexity, as the calculation uses standard sensor data already available in modern engine management systems.
Solution Approach 2:
The system implements feedback by continuously monitoring cooling-related parameters (flow rate, temperature, ambient conditions) and using this information to adjust the maximum temperature threshold in real-time. The control unit receives feedback from sensors and dynamically modifies the threshold to match actual cooling capacity. This feedback mechanism provides adaptability without excessive complexity, as it uses existing sensor infrastructure and straightforward calculation logic.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach accurately limits engine torque to prevent boiling without significantly reducing vehicle performance, especially in high-power situations, thereby extending engine component lifespan and optimizing the quality-performance-cost compromise.
Implementation Method 1
Boiling of the heat transfer fluid can cause several problems. It can damage the internal combustion engine by limiting heat exchange at the walls, making heat exchange less efficient
Implementation Method 2
Boiling can also cause one or more heat transfer fluid pumps in the system to lose their prime. Boiling can cause loss of temperature information if a sensitive element of a heat transfer fluid temperature sensor in the cooling system is no longer receiving water
Data Source
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Figure 3~4
AI summary
The invention relates to a method for limiting the temperature of a heat transfer fluid (T°liq) in a cooling system of an internal combustion engine in a motor vehicle. This method prevents the temperature of the fluid exiting the engine from temporarily exceeding the boiling point of the heat transfer fluid. The limitation is achieved by restricting engine torque based on a predetermined maximum temperature of the heat transfer fluid (maxT°liq) exiting the engine, an instantaneous temperature of the heat transfer fluid (T°liq) exiting the engine, and a vehicle speed (Vveh). The engine torque limitation takes into account at least one parameter selected from among the instantaneous power (Pmot) of the engine, the instantaneous torque of the engine, or the instantaneous heat flux in the engine. Application in the field of motor vehicles.