Exhaust Gas Sensor Heater Control for Thermal Shock Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control systems for exhaust gas sensors in hybrid vehicles with long intermittent shutdowns of internal combustion engines fail to prevent thermal shock and cracking due to condensed water splashing, as they do not adequately account for prolonged shutdown times and moisture condensation.
Innovation Solution
A control apparatus that includes an exhaust gas sensor and a heater with a control device that stops heater energization based on predetermined times set by outside air temperature and cooling water temperature, ensuring the exhaust gas sensor is protected from thermal shock during long shutdown periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater is energized to activate the exhaust gas sensor during shutdown of the internal combustion engine, then the sensor activation is improved, but the risk of cracking due to condensed water splashing increases
Solution Approach 1:
The control device predicts the engine restart timing in advance and stops the heater energization before the predicted restart occurs. This preliminary action prevents condensed water from splashing onto the heated sensor, eliminating the cracking risk while maintaining sensor activation during the shutdown period.
Solution Approach 2:
The control device uses feedback from engine operation states and shutdown duration to dynamically adjust heater control. By monitoring whether the shutdown exceeds a predetermined threshold and predicting restart timing, the system optimizes heater energization to prevent cracking while ensuring sensor activation.
2Loss of energy
If the internal combustion engine is shut down for a long time in a series hybrid vehicle, then fuel efficiency is improved, but condensed water generation increases causing sensor cracking
Solution Approach 1:
The control device predicts engine restart timing in advance based on the extended shutdown period characteristic of series hybrid vehicles. By stopping heater energization before the predicted restart, the system prevents condensed water accumulation during long shutdowns while maintaining fuel efficiency benefits.
Solution Approach 2:
The control device adjusts heater control parameters based on shutdown duration and predicted restart timing. For long shutdowns typical in series hybrid operation, the system modifies heater energization timing to prevent condensed water formation, adapting the thermal management strategy to the extended idle period.
3Object-affected harmful factors
If the heater energization is stopped too early before engine restart, then cracking risk is reduced, but sensor activation may be insufficient
Solution Approach 1:
The control device uses feedback from engine operation states, shutdown duration, and predicted restart timing to optimize heater shutdown timing. This feedback mechanism ensures the heater remains energized long enough for proper sensor activation while stopping before predicted restart to prevent cracking.
Solution Approach 2:
By predicting engine restart timing in advance, the control device can determine the optimal moment to stop heater energization. This preliminary knowledge allows the system to maintain heater operation for sufficient sensor activation while ensuring shutdown occurs before condensed water splashing can cause cracking.
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
Effectively prevents cracking of the exhaust gas sensor by determining the optimal timing for turning off heater energization, reducing the risk of water splashing damage during extended shutdowns of the internal combustion engine.
Implementation Method 1
a heater (8A, 9A) attached to the exhaust gas sensor (7)
Implementation Method 2
an exhaust gas sensor (7) arranged in an exhaust pipe of the internal combustion engine (3) to detect a concentration of oxygen in exhaust gas
Implementation Method 3
stops energization of the heater at a predetermined timing after shutdown of the internal combustion engine
Data Source
AI summary
An apparatus for controlling an internal combustion engine executes air-fuel ratio feedback control based on a detection result of an exhaust gas sensor and when the engine is shut down, stops energization of a heater of the exhaust gas sensor at a predetermined timing after shutdown of the engine, heater control of the exhaust gas sensor is executed, which is suitable for a case in which shutdown time of the engine is set long, and thus the exhaust gas sensor is protected from thermal shock. The control apparatus sets timing for stopping energization of a heater of an exhaust gas sensor after shutdown of the engine, to a point in time when a predetermined time set based on outside air temperature has elapsed, or a point in time when cooling water temperature of the engine has dropped to a predetermined temperature.