Hybrid Oxygen Sensor Heater Control for Early Fuel Trim
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Solution Overview
Problem
Conventional hybrid engine systems activate oxygen sensor heaters after starting the engine, which delays closed-loop fuel control and increases hydrocarbon emissions during the catalyst light-off process.
Innovation Solution
The control system selectively activates the oxygen sensor heaters prior to starting the engine, increasing their temperature above the sensitivity temperature before engine startup, enabling earlier closed-loop fuel control and reducing hydrocarbon emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oxygen sensor heaters are activated after engine startup, then the engine can start immediately without preheating delays, but closed-loop fuel control is delayed and hydrocarbon emissions increase during catalyst light-off
Solution Approach 1:
The oxygen sensor heater is activated before engine startup to preheat the sensor above its sensitivity temperature. This preliminary action ensures the sensor is ready to provide accurate feedback signals immediately when the engine starts, enabling immediate closed-loop fuel control and reducing hydrocarbon emissions during catalyst light-off, while still allowing the engine to start without delay
2Productivity
If oxygen sensor heaters are activated before engine startup, then closed-loop fuel control can begin earlier, but additional energy is consumed to heat the sensors
Solution Approach 1:
The heater is activated only when specific conditions are met (ignition switch in RUN position, engine not yet started), providing preliminary heating only when it will directly benefit immediate closed-loop control operation, avoiding unnecessary energy consumption during other operating conditions
Solution Approach 2:
The heater operation is controlled periodically based on engine operating conditions. The control module monitors whether the engine is running and whether closed-loop control is needed, activating the heater only during appropriate periods when it provides value, rather than continuously or unnecessarily
3Use of energy by moving object
If oxygen sensors are operated below sensitivity temperature, then the system can operate without heater energy consumption, but the sensors cannot provide accurate feedback for closed-loop fuel control
Solution Approach 1:
The control module continuously monitors the oxygen sensor output signal to determine whether the sensor has reached its sensitivity temperature and is providing accurate feedback. This feedback mechanism allows the system to know when the sensor is ready for closed-loop control without needing to continuously heat it, enabling energy-efficient operation when accurate measurement is not yet required
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 allows for earlier determination of fuel trim values and stoichiometric air-to-fuel ratios during catalyst light-off, lowering hydrocarbon emissions and improving fuel efficiency.
Implementation Method 1
The engine control module selectively activates a heater for an oxygen sensor of an exhaust system of the engine during the period
Data Source
AI summary
A control system for a hybrid engine system includes a torque management module and an engine control module. The torque management module operates an electric machine of the hybrid engine system for a period prior to starting an engine of the hybrid engine system for a first time during a current run cycle of the hybrid engine system. The engine control module selectively activates a heater for an oxygen sensor of an exhaust system of the engine during the period. The engine control module may selectively activate the heater prior to the period when an ignition switch for the hybrid engine system moves from an off state into an on state. The engine control module may increase the temperature of the oxygen sensor to a predetermined temperature based on one of a thermal shock temperature and a sensitivity temperature of the oxygen sensor. A related method is also provided.