ECU-Solenoid Harness Resistance Estimation Using a Dummy Harness
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Solution Overview
Problem
The existing solenoid valve systems in automotive applications face challenges in accurately estimating the resistance of the harness due to varying ambient temperatures and pulsed current conditions, leading to inaccuracy in thermal protection and heat exchange modeling.
Innovation Solution
A method is introduced that involves using a dummy harness connected between the Engine Control Unit (ECU) and a solenoid operated valve, where a current is passed through the dummy harness to match the heat exchange of the actual harness, allowing for the determination of the actual harness resistance by measuring power consumption and using known reference resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the coil resistance is reduced to minimize heat released by the Joule effect, then the heat generation is reduced, but the electrical resistance contrast between the coil and the harness decreases, making harness resistance estimation inaccurate
Solution Approach 1:
The patent introduces a dummy harness as an intermediary object that replicates the thermal and electrical characteristics of the actual harness. By measuring the dummy harness under controlled conditions and using these measurements to infer the actual harness resistance, the system can accurately estimate harness resistance even when the coil resistance is low and the direct contrast method fails.
Solution Approach 2:
The patent creates a copy of the actual harness (the dummy harness) that mimics its electrical resistance and thermal properties. The dummy harness is subjected to the same current conditions and ambient temperature, allowing its measured resistance to serve as an accurate proxy for the actual harness resistance, thereby solving the measurement accuracy problem.
2Device complexity
If model-based estimation is used for harness resistance, then the estimation process is simple, but the accuracy becomes insufficient when coil resistance is low and heat exchange varies with temperature
Solution Approach 1:
The dummy harness serves as a mediator that bridges the gap between simple measurement and accurate results. Instead of relying on complex models or simple inaccurate estimations, the dummy harness provides a physical reference that can be measured directly, achieving high accuracy without requiring complex computational models.
3Adaptability or versatility
If the harness resistance estimation is performed under varying ambient temperature and pulsed current conditions, then the system adapts to real operating conditions, but the heat exchange cannot be accurately modeled
Solution Approach 1:
The patent performs preliminary action by pre-characterizing the dummy harness under various temperature and current conditions. The dummy harness is exposed to the same ambient temperature and current pulse patterns as the actual harness before measurement, allowing the system to adapt to real operating conditions while maintaining measurement accuracy through the controlled dummy reference.
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 enables accurate determination of the harness resistance under variable ambient temperatures and current conditions, improving the estimation accuracy and thermal protection of the solenoid valve systems.
Implementation Method 1
passing a current through the dummy harness (I D ) such that the heat exchange to the environment is substantially the same as that in the actual harness
Data Source
Figure 1~2
AI summary
In an engine system, a method of determining the electrical resistance of an actual harness R H (θ H ), connecting the Engine Control Unit (ECU) to one or more a solenoid operated valves comprising: a) providing a dummy harness connected at one end to the ECU and at the other end to a terminal connection in the vicinity of the solenoid valve; b) determining the estimated RMS current (Is) through the actual harness; c) passing a current through the dummy harness (ID) such that the heat exchange to the environment is substantially the same as that in the actual harness; d) measuring the power consumption in the dummy harness; e) from the results from b) and d) determining the resistance of the actual harness.