O2 Sensor Heater Control for Hybrid Cold-Start Emissions
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Solution Overview
Problem
Existing vehicle exhaust systems struggle with high emissions during cold starts due to the inability of cold three-way catalytic converters to efficiently convert pollutants, relying on inaccurate open loop fueling and complex airflow models that require long calibration times.
Innovation Solution
Implementing oxygen (O2) sensor heaters to pre-heat sensors to a predetermined target temperature before engine start, enabling immediate closed loop fueling control and reducing dependency on airflow models, thereby ensuring accurate fuel delivery and minimizing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open loop fueling control with complex airflow models is used during cold start, then the system can operate without feedback control, but emissions are higher and fuel delivery has more variation
Solution Approach 1:
The system performs preliminary heating of the O2 sensor before engine start during EV mode, so that the sensor is already at operating temperature and ready for immediate closed loop feedback control when the engine starts, eliminating the need for open loop operation
Solution Approach 2:
The system implements closed loop feedback control using the pre-heated O2 sensor to monitor exhaust oxygen levels and adjust fuel delivery in real-time, reducing emissions and fuel variation compared to open loop control
2Productivity
If the O2 sensor is heated before engine start in EV mode, then closed loop fueling control can begin immediately, but additional heating energy is consumed
Solution Approach 1:
The O2 sensor is pre-heated during EV mode before engine start, so that when the engine starts, the sensor is already at operating temperature and ready for immediate closed loop control, eliminating the warm-up delay
Solution Approach 2:
The heating element operates periodically or in pulses during EV mode to bring the sensor to temperature, rather than continuous heating, optimizing energy usage while achieving the target temperature
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
The system reduces tailpipe emissions of hydrocarbons (HC) and nitrogen oxides (NOx) by allowing immediate closed loop fueling control, minimizing fuel variations and emissions during cold starts.
Implementation Method 1
the at least one O2 sensor includes a heating element configured to heat the at least one O2 sensor
Data Source
AI summary
A control system for a hybrid electric vehicle having an electric drive module and an internal combustion engine with an exhaust system. The control system includes one or more oxygen (O2) sensors disposed proximate to a catalytic converter in the exhaust system, the one or more O2 sensors each being configured to measure an O2 level of exhaust gas produced by the engine. A controller is in signal communication with the one or more O2 sensors and programmed to detect the hybrid electric vehicle is keyed on, determine the hybrid electric vehicle is keyed to run in an electric vehicle (EV) mode without the engine started, and initiate an O2 sensor heating mode to heat the one or more O2 sensors to a predetermined target temperature prior to the engine starting. The predetermined target temperature is operable for closed loop fueling feedback control, to thereby reduce exhaust emissions.