UEGO Sensor Heater Control for Crack Prevention
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Solution Overview
Problem
Existing methods for activating Universal Exhaust Gas Oxygen (UEGO) sensors during the pre-delivery and post-delivery phases of a vehicle face challenges such as sensor cracking due to sudden temperature changes and inefficient emissions control, particularly during short engine operation durations and cold-start conditions.
Innovation Solution
Adjusting the electric current to the UEGO sensor heater, using a lower gain during the pre-delivery phase for gradual heating and a higher gain during the post-delivery phase for expedited heating, along with retarding spark timing when necessary, to minimize the risk of sensor cracking and ensure timely emissions control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If heating of the UEGO sensor is expedited during short but frequent engine operations in the pre-delivery phase, then sensor activation time is reduced, but water condensate formed on the sensor elements may cause cracks in the sensor
Solution Approach 1:
The patent applies dynamics by making the heater control strategy adaptive based on vehicle phase. The controller dynamically switches between pre-delivery mode (gradual heating with lower gain) and post-delivery mode (expedited heating with higher gain) to optimize both sensor reliability and activation time for different operational contexts
Solution Approach 2:
The patent changes the control parameter (heater gain) based on vehicle phase. During pre-delivery phase, a lower gain is used for gradual heating, while during post-delivery phase, a higher gain is used for expedited heating. This parameter adjustment resolves the contradiction by adapting the heating rate to the specific operational context
2Temperature
If retarding ignition timing is used to increase exhaust temperature for UEGO sensor activation, then sensor heating is improved, but fuel consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-heating the UEGO sensor using the heater element before relying on exhaust temperature. This allows the sensor to reach activation temperature without requiring extensive ignition timing retardation, thereby reducing fuel consumption while still achieving proper sensor heating
Solution Approach 2:
The patent introduces the UEGO sensor heater as an intermediary device to achieve sensor activation. Instead of directly increasing exhaust temperature through ignition timing retardation (which consumes fuel), the heater element serves as an intermediary that efficiently heats the sensor with minimal impact on fuel consumption
3Productivity
If a higher current is applied to the UEGO heater during pre-delivery phase, then sensor activation is faster, but the possibility of sensor elements cracking increases
Solution Approach 1:
The patent makes the heater current dynamic by adjusting it based on vehicle phase. During pre-delivery phase, a lower current is used to prevent cracking, while during post-delivery phase, a higher current is used to expedite activation. This dynamic adjustment resolves the contradiction between activation speed and reliability
Solution Approach 2:
The patent changes the electrical parameter (heater current) based on operational phase. The controller adjusts the current magnitude from lower (pre-delivery) to higher (post-delivery) to optimize the balance between activation speed and sensor element integrity for each phase
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 optimizes UEGO sensor activation, reducing the likelihood of sensor degradation and improving fuel economy and emissions performance by allowing for gradual heating during pre-delivery and rapid activation post-delivery, without altering engine operating parameters.
Implementation Method 1
a UEGO sensor heater may be operated to heat the sensor to a threshold temperature, thereby activating the sensor
Data Source
AI summary
Methods and systems are provided for activating a universal exhaust gas oxygen (UEGO) sensor activation during each of a pre-delivery phase and a post-delivery phase of a vehicle. In one example, a method may include during the pre-delivery phase, following an engine start, using a lower current flowing via a heater coupled to the UEGO sensor to heat the UEGO sensor and during the post-delivery phase, following an engine start, once exhaust temperature reaches a threshold temperature, using a higher current flowing via the heater coupled to the UEGO sensor to heat the UEGO sensor.