Iterative Engine Thermal Model for Coolant Temperature Estimation
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Solution Overview
Problem
Existing cooling circuit systems for motor vehicle engines face challenges in accurately measuring coolant temperature during engine start-up when the cooling fluid is not circulating, leading to inefficient engine operation and suboptimal cooling regulation.
Innovation Solution
A control device with an iterative temperature estimation module models heat exchanges at multiple thermal nodes, using engine operating parameters and previous temperature estimates to correct estimated coolant temperatures based on measurement differences, ensuring reliable temperature representation until the engine reaches optimal operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling circuit is temporarily maintained in an inactive state to accelerate engine warming, then the engine reaches optimal operating temperature faster, but the coolant temperature measurement becomes unreliable and cannot represent the average engine temperature
Solution Approach 1:
The patent introduces a thermal model as an intermediary system that estimates coolant temperature based on engine operating parameters (load, speed, ambient temperature) and heat exchange calculations. This model acts as a mediator between the inactive cooling circuit and the temperature measurement system, providing reliable temperature information during periods when direct measurement would be inaccurate.
Solution Approach 2:
The patent replaces the direct mechanical/physical measurement system (temperature sensor in circulating coolant) with a computational model during the inactive period. The thermal model uses mathematical calculations based on heat transfer principles to substitute for the physical temperature measurement that would otherwise be unavailable or inaccurate.
2Productivity
If the cooling fluid circulation is limited or prevented during engine start-up, then the engine warms up more efficiently, but the cooling regulation device loses accurate temperature information for control decisions
Solution Approach 1:
The patent implements a feedback mechanism where the thermal model continuously receives updated engine operating parameters (load, speed, ambient conditions) and adjusts its temperature estimates accordingly. This feedback loop ensures that the model maintains accurate temperature information throughout the inactive period, enabling the cooling regulation device to make informed control decisions.
Solution Approach 2:
The patent performs preliminary calculations of temperature evolution during the inactive period using the thermal model. By predicting temperature trends before the cooling circuit becomes active, the system prepares accurate temperature information in advance, preventing information loss and enabling proactive control decisions.
3Reliability
If a thermal model with multiple thermal nodes is used to estimate temperatures, then reliable temperature information is obtained during inactive state, but the device complexity increases
Solution Approach 1:
The patent divides the engine thermal system into multiple discrete thermal nodes (coolant, engine block, cylinder head, oil) that can be independently modeled and calculated. This segmentation allows the complex thermal system to be broken down into manageable computational units, each with its own heat balance equations, making the overall model more tractable and implementable.
Solution Approach 2:
The thermal model serves multiple functions simultaneously: it estimates coolant temperature for regulation control, predicts engine component temperatures for performance optimization, and provides diagnostic information about thermal states. This multi-functionality justifies the added complexity by delivering comprehensive thermal management capabilities from a single integrated model.
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 solution enables accurate temperature monitoring and correction during engine start-up, ensuring efficient engine warming and preventing overheating, thereby improving cooling circuit regulation and overall engine performance.
Implementation Method 1
The invention consists in modeling the heat exchanges in the engine by a system with several thermal nodes each characterizing a temperature of a solid or liquid physical element of the engine
Data Source
Figure 1~2
AI summary
A cooling circuit for a vehicle engine notably comprises a possibility for adjusting, under the control of a control device, the rate at which a coolant circulates in this circuit. The control device, in successive iterations, makes N estimates of the temperature at N engine temperature nodes, supplemented by an (N + 1)- th estimate of the temperature of the coolant. These (N+1) estimates are made on the basis of M input signals which are associated with M engine operating parameters and from the (N+1) estimates made earlier. To correct the estimates, the control device comprises a comparison module (23) comparing the estimated temperature of the coolant against an actual measurement of this temperature, and a first correction stage (24, 25) for correcting the (N+1) estimates, possibly supplemented by a second correction stage (31, 32, 33, 34) for correcting the M input signals.