Exhaust Gas Sensor Activation Timing via Adsorbed Species Desorption
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Solution Overview
Problem
Existing air-fuel ratio control systems for internal combustion engines face challenges in accurately determining the activation state of exhaust gas sensors due to the lingering effects of adsorbed species, which cause output shifts and inhibit early use of sensor data, even after the sensor reaches activation temperature.
Innovation Solution
A device and control system that determine the activation state of exhaust gas sensors by measuring the elapsed time after the adsorbed species have desorbed, using a heater to reach a predetermined temperature and considering the elimination of adsorbed species' effects, ensuring accurate air-fuel ratio control by delaying activation until the sensor output is stable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the exhaust gas sensor is heated to activation temperature early, then early air-fuel ratio control is enabled, but adsorbed species cause output shifts and inaccurate measurements
Solution Approach 1:
The system performs preliminary heating of the exhaust gas sensor to a first temperature before reaching the full activation temperature. This preliminary action removes adsorbed species that would otherwise cause output shifts, enabling accurate measurements to start earlier without sacrificing measurement precision
Solution Approach 2:
The invention changes the temperature parameter dynamically by heating the sensor to different temperatures at different stages. First, a lower temperature is used to remove adsorbed species, then the temperature is increased to activation temperature for accurate measurements, optimizing both timing and precision
2Measurement precision
If the exhaust gas sensor output is masked until regular activation state, then accurate measurement is ensured, but early air-fuel ratio control is delayed
Solution Approach 1:
The system performs preliminary heating to remove adsorbed species before the sensor reaches full activation temperature. This preliminary action clears the way for early accurate measurements, allowing air-fuel ratio control to start earlier without compromising measurement precision
Solution Approach 2:
The invention uses dynamic temperature parameter changes, first heating to a lower temperature to eliminate adsorbed species effects, then increasing to activation temperature. This enables the sensor output to be used earlier while maintaining 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 effectively suppresses the adverse effects of adsorbed species, allowing for early and accurate use of exhaust gas sensor output, improving air-fuel ratio control and reducing harmful effects on engine performance and drivability.
Implementation Method 1
a heater (57) for heating the exhaust gas sensor (48)
Implementation Method 2
an exhaust gas sensor (48) which issues an output corresponding to an air-fuel ratio of an exhaust gas
Implementation Method 3
the adsorbed species start to be desorbed
Data Source
Figure 1~2
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AI summary
The invention has an object to provide a device for determining activation of an exhaust gas sensor which accurately determines a time at which an exhaust gas sensor output is usable, and can suppress an adverse effect caused by use of the exhaust gas sensor output including a large effect of adsorbed species. A time is measured from a time point when a temperature of an air-fuel ratio sensor 48 reaches a predetermined temperature T1, while the air-fuel ratio sensor 48 is warmed up. When the time becomes a predetermined target holding time Te or more, the air-fuel ratio sensor 48 is determined as being in an activation state. The target holding time Te is preferably set at such a length that all adsorbed species adsorbed onto the air-fuel ratio sensor 48 are desorbed, and areas around a sensor element section 50 are completely replaced with an exhaust gas.