Low Coolant Temperature Fault Diagnostic System
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Solution Overview
Problem
Internal combustion engines face challenges in diagnosing low engine coolant temperature faults, particularly when stationary or moving slowly, leading to potential overheating and reduced engine reliability due to inadequate heat dissipation.
Innovation Solution
A diagnostic system comprising a comparison module, disabling module, and fault indication module that monitors engine coolant temperature, disabling fault diagnosis until the temperature exceeds a predetermined level to prevent false alarms and allowing the coolant to warm up, thereby preventing erroneous fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the vehicle is stationary or moving slowly, then the cooling fan may be required to increase heat transfer, but the engine coolant may be unable to release heat effectively leading to overheating
Solution Approach 1:
The patent implements dynamic fault diagnosis by enabling the low coolant temperature fault only when the vehicle is moving above a threshold speed, rather than using a static diagnosis approach. This dynamic condition adapts the diagnostic system to actual operating conditions, preventing false alarms during stationary or slow-moving operations while maintaining reliability during normal driving conditions
2Temperature
If the cooling fan is turned ON to draw air past the radiator, then heat transfer increases, but the system complexity and energy consumption increase
Solution Approach 1:
The patent allows the vehicle's motion itself to serve as the cooling mechanism by utilizing natural airflow through the radiator when the vehicle is moving. The cooling fan becomes unnecessary during normal driving conditions, as the vehicle's forward motion automatically provides sufficient airflow for heat dissipation, eliminating the need for additional energy-consuming cooling components
3Reliability
If fault diagnosis is performed continuously, then early fault detection is possible, but false alarms occur when coolant temperature is low due to vehicle stationary or slow movement
Solution Approach 1:
The patent implements dynamic fault diagnosis by enabling the low coolant temperature fault only when the vehicle is moving above a threshold speed, rather than using a static diagnosis approach. This dynamic condition adapts the diagnostic system to actual operating conditions, preventing false alarms during stationary or slow-moving operations while maintaining reliability during normal driving conditions
Solution Approach 2:
The patent uses vehicle speed as a feedback parameter to control the fault diagnosis logic. The ECU continuously monitors vehicle speed and uses this information to determine whether to enable or disable the low coolant temperature fault diagnosis, creating a feedback loop that prevents false alarms while maintaining accurate fault detection
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
The system effectively diagnoses low coolant temperature faults, preventing false alarms and ensuring accurate detection, which helps in maintaining engine reliability by ensuring proper coolant circulation and heat management.
Implementation Method 1
The engine coolant absorbs heat from the engine
Implementation Method 2
The radiator transfers heat from the engine coolant to air passing the radiator
Data Source
AI summary
A diagnostic system for a vehicle includes a comparison module, a disabling module, and a fault indication module. The comparison module indicates whether a temperature of engine coolant is less than a first predetermined temperature. The disabling module disables the comparison module until the temperature of the engine coolant is greater than a second predetermined temperature. The fault indication module diagnoses a fault in response to the comparison module indicating that the temperature of the engine coolant is less than the first predetermined temperature.