Coolant Substitution Temperature Calculation for Engine Control
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Solution Overview
Problem
The activation of an additional heater in vehicles before starting the engine leads to an erroneous coolant temperature measurement due to thermal conduction, causing issues like poor combustion, engine stalling, and increased emissions, as the temperature sensor acquires a temperature that does not represent the overall thermal state of the heat engine.
Innovation Solution
A method to calculate a substitution temperature by determining the temperature difference from heating profiles and using a weighting coefficient to interpolate and correct the measured temperature, ensuring accurate engine control by transmitting this substitution temperature to the engine computer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the additional heater is activated to warm the passenger compartment before engine start, then the comfort of the user is improved, but the temperature sensor acquires an erroneous temperature that does not represent the overall thermal state of the heat engine
Solution Approach 1:
The cooling circuit is segmented into two separate loops: a short loop that circulates coolant through the additional heater and a portion of the radiator, and a long loop that circulates coolant through the entire cooling circuit including the engine. This segmentation allows the additional heater to operate independently without significantly heating the coolant in the long loop, thus preventing erroneous temperature measurements while maintaining user comfort.
Solution Approach 2:
A non-return valve is introduced as an intermediary element to control the direction of coolant flow. This valve ensures that coolant flows only through the short loop when the additional heater is activated, preventing heated coolant from entering the long loop and reaching the temperature sensor, thereby eliminating measurement errors while preserving the heating function.
2Ease of operation
If the additional heater heats the coolant in the long loop through thermal conduction, then the passenger compartment can be warmed, but this causes poor combustion, engine stalling, and increased emissions
Solution Approach 1:
The cooling circuit is divided into separate loops to isolate the thermal effects of the additional heater from the engine cooling system. By preventing heated coolant from circulating through the engine, the engine maintains its required thermal state for stable operation, while the passenger compartment still receives heating from the additional heater through the short loop.
Solution Approach 2:
The non-return valve acts as a mediator that controls coolant flow direction, ensuring that heated coolant from the additional heater does not enter the long loop and affect the engine. This intermediary element preserves both the heating function for comfort and the thermal stability required for reliable engine operation.
3Measurement precision
If the additional heater is used with a short loop configuration, then the temperature sensor measurement error is reduced, but the device complexity increases due to additional valves and circuit modifications
Solution Approach 1:
The additional heater system is designed to perform multiple functions: it can heat the passenger compartment through the short loop when needed, and it can allow normal coolant circulation through the long loop when not in use. The solenoid valve and non-return valve are configured to automatically route coolant flow based on operational requirements, providing universal functionality without requiring separate systems for heating and cooling.
Solution Approach 2:
The cooling circuit incorporates dynamically controllable valves (solenoid valve and non-return valve) that automatically adjust coolant flow paths based on operational conditions. This dynamic configuration allows the system to switch between short loop and long loop modes, optimizing both measurement accuracy and heating efficiency without manual intervention or complex fixed modifications.
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 eliminates engine instabilities and non-starts by providing a reliable thermal state representation to the engine control system, reducing fuel consumption and emissions, and is cost-effective with no organic modifications required.
Implementation Method 1
the activation of the heater 1 generates an increase in the temperature of the liquid in the long loop by thermal conduction
Data Source
Figure 1~2
Figure 3a~3b
AI summary
The invention mainly concerns a method for determining a substitution temperature (Ts) for substituting a coolant liquid at a measured temperature (Tm) in order to control a heat engine, said heat engine being combined with a cooling circuit in connection with an additional heater, characterised in that, when said additional heater has been used prior to the starting of the heat engine, said method comprises: - a step of calculating said substitution temperature (Ts) from heating profiles of the coolant liquid depending, in particular, on an activation period (Dact) of said additional heater, and - a step of transmitting said substitution temperature (Ts) to an engine computer in order to ensure the control of said heat engine.