EHC Temperature Estimation Using Power and Ambient Air Data
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Solution Overview
Problem
Existing technologies have struggled to accurately measure the temperature of an electrically heated catalyst (EHC) by means of an EHC control device.
Innovation Solution
A device capable of accurately estimating the temperature of a heated object by using a power detection unit, an arithmetic unit, and a temperature determination unit to estimate the temperature of a heated object without directly measuring it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is embedded in the EHC to directly measure temperature, then temperature measurement accuracy is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent uses power consumption data and ambient temperature as intermediary parameters to indirectly estimate the EHC temperature. Instead of directly measuring temperature with a sensor inside the EHC, the system uses the relationship between power input, ambient conditions, and thermal characteristics to calculate temperature, thereby avoiding the need for complex embedded sensing hardware.
Solution Approach 2:
The patent replaces the mechanical/physical temperature sensor with an computational model that uses electrical measurements (power consumption) and environmental data to estimate temperature. This substitution eliminates the need for physical sensor embedding while maintaining temperature information through mathematical modeling.
2Device complexity
If NTC characteristics are used to estimate temperature based on resistance value, then device complexity is reduced, but temperature estimation accuracy deteriorates at higher temperatures
Solution Approach 1:
The patent changes the parameter used for temperature estimation from resistance value (NTC characteristic) to power consumption data. By using power consumption along with ambient temperature and thermal characteristics, the system achieves accurate temperature estimation across the full temperature range without relying on the deteriorating NTC characteristics at high temperatures.
3Measurement precision
If power detection and external air temperature are used to estimate heated object temperature, then temperature estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The system uses power consumption data that is already being monitored for control purposes and combines it with ambient temperature measurements to self-determine the EHC temperature. This approach leverages existing data collection infrastructure, avoiding the need for additional dedicated temperature sensing hardware while improving temperature estimation accuracy.
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
Accurately estimates the temperature of the heated object by using power detection and external air temperature, enabling precise control and prevention of undesirable temperature ranges.
Implementation Method 1
an in-vehicle heated object that is heated by current flow
Implementation Method 2
an arithmetic unit that performs a computation to estimate a temperature of a location in the heated object based on supplied power and temperature of external air
Data Source
AI summary
An in-vehicle temperature estimation device is applied to an in-vehicle heated object heated by current flow. The in-vehicle temperature estimation device includes a power detection unit for detecting the supplied power supplied to the heated object, an arithmetic unit that performs a computation to estimate the temperature of a first location in the heated object, and a temperature determination unit that determines the temperature of the external air outside the heated object. The arithmetic unit performs a computation to estimate the temperature at the first location based on the supplied power detected by the power detection unit and the temperature of the external air determined by the temperature determination unit.