Exhaust Gas Sensor Preheat Control for Engine Stop-Start
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Solution Overview
Problem
In internal combustion engines with automatic stop-restart control, the preheat control of exhaust gas sensors leads to increased reactivation periods, affecting fuel efficiency and exhaust emission accuracy due to varying sensor deterioration and battery charge levels.
Innovation Solution
A control unit adjusts the preheat temperature of the exhaust gas sensor based on the deterioration condition and battery charge, setting it to a first or second preheat temperature depending on whether the reactivation period exceeds a predetermined period, to optimize reactivation speed and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If preheat control is executed by decreasing electric power supply to the heater, then electric power consumption is reduced and fuel efficiency is improved, but the reactivation period becomes excessively long
Solution Approach 1:
The preheat temperature is made dynamically adjustable based on sensor deterioration degree and battery charge amount. The control unit switches between first preheat temperature (lower, for power saving) and second preheat temperature (higher, for faster reactivation) depending on current system conditions, resolving the contradiction between power consumption and reactivation speed
Solution Approach 2:
The preheat temperature parameter is changed based on sensor deterioration degree and battery charge amount. When sensor deterioration is high or battery charge is low, the preheat temperature is increased to ensure adequate reactivation speed, while under normal conditions the lower preheat temperature is used to save power
2Loss of energy
If preheat temperature is set to first preheat temperature (lower temperature), then electric power consumption is reduced, but reactivation speed becomes slow
Solution Approach 1:
The system dynamically selects between first preheat temperature and second preheat temperature based on real-time conditions including sensor deterioration degree and battery charge amount, optimizing the balance between power consumption and reactivation speed
Solution Approach 2:
The control unit monitors sensor deterioration degree and battery charge amount, using this feedback information to determine the appropriate preheat temperature setting, ensuring optimal performance under varying conditions
3Reliability
If preheat control is executed continuously, then sensor element temperature is maintained, but electric power consumption increases
Solution Approach 1:
Instead of continuous heating, the system uses periodic preheat control only when the engine is stopped and restart is imminent. The preheat temperature is temporarily adjusted during these periods, reducing overall power consumption while maintaining sensor reliability when needed
Solution Approach 2:
The preheat control is executed in advance before engine restart is needed, preparing the sensor element for quick activation. This preliminary action ensures the sensor is ready for operation without requiring continuous heating, thus reducing power consumption
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 reduces the reactivation period and minimizes fuel efficiency deterioration and exhaust emission issues by dynamically adjusting the preheat temperature in response to sensor condition and battery charge, ensuring accurate engine control.
Implementation Method 1
a heater that heats a sensor element
Data Source
AI summary
A sensor system for an engine for which an automatic stop-restart control is performed, the sensor system including: an exhaust gas sensor including a heater that heats a sensor element; and a control unit configured to: while the engine is stopped by the automatic stop-restart control, execute a preheat control of adjusting a temperature of the sensor element to a preheat temperature lower than an activation temperature; when an automatic start condition is satisfied, stop the preheat control and increase the temperature of the sensor element to the activation temperature; when an automatic stop condition is satisfied and a delay condition has not been satisfied, set the preheat temperature to a first temperature; and when the automatic stop condition is satisfied and the delay condition has been satisfied, set the preheat temperature to a second temperature higher than the first temperature.