Diesel Gas Sensor Heater Control for Water Damage Prevention
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Solution Overview
Problem
Conventional heater controlling apparatuses for diesel engine gas sensors fail to consider the influence of condensed water in the exhaust system, leading to potential damage of the sensing element when energizing the heater, and may delay heater activation, thereby reducing exhaust gas purification efficiency.
Innovation Solution
A heater controlling apparatus that adjusts its reference conditions based on the operational state before engine stop, delaying heater energization when condensed water is likely present to ensure its removal, and adjusting reference temperatures and times accordingly to prevent sensing element exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater energization is started when the wall temperature reaches a threshold, then the sensing element can be heated to activate the gas sensor, but condensed water in the exhaust system may attach to the sensing element surface and cause breakage
Solution Approach 1:
The control apparatus performs preliminary actions by delaying heater energization until the exhaust temperature reaches a higher threshold (second threshold higher than first threshold) or a predetermined time elapses after engine start. This preliminary delay ensures condensed water is evaporated or removed before the sensing element is heated, preventing water attachment and breakage while maintaining reliable sensor activation
Solution Approach 2:
The invention changes the temperature parameter threshold for heater energization from a fixed first threshold to a dynamic second threshold that is higher than the first threshold. This parameter change allows the system to distinguish between different operational states (idle vs. running) and adjust the heater activation timing accordingly, preventing water damage while ensuring timely sensor activation
2Reliability
If the heater energization is delayed to prevent water damage to the sensing element, then the sensing element is protected from breakage, but the gas sensor activation is unnecessarily delayed and exhaust gas purification efficiency is reduced
Solution Approach 1:
The control apparatus dynamically adjusts the heater energization timing based on real-time detection of engine operational state. When the engine is detected to be in an idle state with low exhaust temperature, the system dynamically delays heater activation to prevent water damage. When the engine transitions to running state with higher exhaust temperature, the system dynamically advances heater activation to maintain efficient sensor operation, thus optimizing both protection and timing
3Device complexity
If the heater energization is based only on wall temperature information, then the control is simple, but condensed water accumulation from preceding low-temperature operation is not considered
Solution Approach 1:
The control apparatus implements feedback by continuously monitoring engine operational state parameters (exhaust temperature, engine running state) and using this feedback information to adjust heater energization timing. The system feedbacks from the detected operational state to determine whether the engine is in idle or running condition, and accordingly adjusts the heater activation timing to account for condensed water accumulation risks, improving detection accuracy while maintaining manageable control complexity
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 sensing element damage by ensuring the removal of condensed water before heater activation, allowing for timely and efficient gas sensor activation and maintaining exhaust gas purification efficiency.
Implementation Method 1
a sensing element needs to be heated to an appropriate temperature by a heater in order to activate the sensing element
Implementation Method 2
condensed water may be accumulated (left) in the exhaust system because of the continuous state of the low exhaust temperature
Data Source
AI summary
A heater controlling apparatus for controlling a heater that heats a sensing element of a gas sensor provided in an exhaust system of a diesel engine includes a device that changes a reference condition for controlling the heater after a start of the engine in a first operation based on an operational state before a stop of the engine in a second operation, which precedes the first operation.