Engine Temperature Correction Using Injector Coil Resistance
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Solution Overview
Problem
The internal combustion engine control device faces challenges in accurately calculating engine temperature based on injector temperature, leading to deviations and deteriorated drivability, especially during startup and restart cycles, due to the self-generated heat of the injector and changes in its correlation with the engine temperature.
Innovation Solution
An internal combustion engine control device is developed with an injector-temperature calculation unit, an internal-combustion-engine temperature calculation unit, and an operating-state control unit, including a cold/warmed-up state determination unit, an ambient-temperature calculation unit, and a correction unit that adjusts the engine temperature calculation based on the difference between injector and ambient temperatures, and decreases the correction amount over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel injection system is adopted to reduce exhaust gas, then emission control is improved, but the cost of the system increases due to additional sensors and components
Solution Approach 1:
The patent extracts and eliminates the temperature sensor from the fuel injection system by using the injector coil resistance value as a substitute indicator. This removes the need for additional sensing components while maintaining the ability to detect engine thermal state for proper fuel injection control.
Solution Approach 2:
The patent uses the injector coil resistance value as an intermediary parameter to indirectly determine engine temperature. Instead of directly measuring temperature with a sensor, the system uses the electrical resistance of the injector coil, which changes with temperature, as a proxy indicator.
2Measurement precision
If the temperature sensor is installed in the internal combustion engine to detect warmed-up state, then fuel injection control accuracy is improved, but the device complexity and cost increase due to wires, couplers, and processing requirements
Solution Approach 1:
The patent removes the temperature sensor and its associated installation components (wires, couplers, processing) by using the existing injector coil resistance measurement to infer engine temperature. This eliminates the need for physical temperature sensing hardware while maintaining control accuracy.
Solution Approach 2:
The injector coil serves dual purposes: it performs its primary function of driving the injector valve and simultaneously serves as a temperature sensing element through its coil resistance. The existing component performs the sensing function without requiring separate dedicated sensing hardware.
3Productivity
If the engine is restarted immediately after stop before temperature rises, then productivity is maintained, but the estimated engine temperature deviates from actual temperature due to high injector temperature
Solution Approach 1:
The patent implements a feedback correction mechanism where the control unit continuously monitors the difference between estimated and actual engine temperature conditions. When restart conditions are detected (high coil resistance indicating cold engine despite recent operation), the system applies correction values to the estimated temperature to compensate for injector self-heating effects.
Solution Approach 2:
The patent dynamically adjusts the temperature estimation parameter by applying different correction values based on operating conditions. The control unit modifies the estimated engine temperature calculation according to the detected restart state, using predetermined correction values to compensate for the non-linear relationship between injector coil resistance and actual engine temperature during restart conditions.
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 effectively corrects the engine temperature calculation, ensuring it aligns with the actual engine temperature, thereby improving drivability by addressing deviations caused by injector temperature discrepancies, without the need for additional temperature sensors.
Implementation Method 1
a self-generated heat amount of the injector increases to raise the temperature of the injector
Data Source
AI summary
An internal combustion engine control device (1) includes an injector-temperature calculation unit (21a), an engine-temperature calculation unit (21b), an operating-state control unit (21c), a cold/warmed-up state determination unit (21d), an ambient-temperature calculation unit (21e), and a correction unit (21f). The correction unit (21f) corrects an engine temperature calculated based on an injector temperature, when it is determined that an engine is in a cold state and a difference between the injector temperature and an ambient temperature is equal to or larger than a first predetermined value.