Engine Control Unit Block Heater Detection Logic
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Solution Overview
Problem
Conventional methods for detecting a block heater in an automobile often result in false indications of engine malfunctions due to temperature differentials between engine coolant and intake air temperatures, which can be influenced by the placement and configuration of sensors and the block heater's effect on coolant temperature.
Innovation Solution
The method involves using an engine control unit to determine the temperature difference between the maximum and minimum engine coolant temperatures over specific time periods, comparing this difference to a predetermined threshold to accurately detect the presence of a block heater and mask false malfunction detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional methods use temperature difference detection after a fixed time period, then the detection process is simple, but false malfunction indications occur due to block heater effects on coolant temperature
Solution Approach 1:
The patent transitions from static fixed-time temperature difference detection to dynamic multi-stage temperature monitoring. The system continuously monitors ECT at multiple time points (initial, intermediate, final) and compares temperature changes across different stages, allowing the detection logic to adapt to the dynamic thermal behavior caused by block heaters, thereby eliminating false malfunction indications while maintaining reasonable system complexity
Solution Approach 2:
The patent applies preliminary action by detecting and recording the initial ECT temperature rise caused by the block heater before making malfunction determinations. The system identifies the initial temperature increase, waits for the temperature to stabilize, and then performs the malfunction detection based on the stabilized temperature reading, thereby preventing false positives while maintaining detection accuracy
2Speed
If the ECT sensor is placed near the block heater, then the sensor responds quickly to temperature changes, but the temperature differential between ECT and IAT becomes exaggerated, causing false malfunction detection
Solution Approach 1:
The patent introduces time as an intermediary element between the ECT sensor reading and the malfunction determination. Instead of immediately interpreting the ECT reading, the system waits for the temperature to stabilize over a predetermined period, allowing the thermal influence of the block heater to dissipate. This temporal intermediary enables accurate malfunction detection regardless of sensor placement relative to the block heater
3Reliability
If the engine is soaked for a long period before detection, then the temperature differential between ECT and IAT normalizes, but the detection time is extended
Solution Approach 1:
The patent applies preliminary action by detecting and recording the initial ECT temperature rise caused by the block heater before making malfunction determinations. The system identifies the initial temperature increase, waits for the temperature to stabilize, and then performs the malfunction detection based on the stabilized temperature reading, thereby preventing false positives while maintaining detection 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
This approach allows for precise detection of block heater presence, preventing false engine malfunction diagnoses by accounting for initial temperature rises and falls caused by the block heater's operation, thereby ensuring accurate engine performance monitoring.
Implementation Method 1
a block heater is an accessory used to heat an engine block... heating the engine block with a block heater generally raises an engine coolant temperature
Implementation Method 2
The radiator delivers coolant to the engine to cool the engine
Implementation Method 3
a fan which forces air over the radiator to cool the coolant
Data Source
AI summary
The present invention relates to a method and system for detecting a presence of a block heater in an automobile. In one embodiment, an automobile includes an engine, a radiator, an engine coolant temperature (“ECT”) sensor, and/or an engine control unit (“ECU”). The radiator delivers coolant to the engine to cool the engine. The ECT sensor is located in a path of the coolant and determines ECT data. The ECU determines a temperature difference between a current maximum temperature of the engine coolant temperature data at a first time period and a current minimum temperature of the engine coolant temperature data at a second time period after the first time period. When the temperature difference is greater than a predetermined temperature threshold, the ECU determines that the block heater is present. When the block heater is present, the ECU masks any engine malfunction detections.