Air Charger Icing Detection Using Calculated Pressure
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Solution Overview
Problem
Conventional air charger systems face issues during part load operation in cold climates due to water vapor condensation or freezing in the charge air cooler, leading to intake air restriction and potential engine failure.
Innovation Solution
A method to detect and mitigate air charger system deficient states by calculating charge air cooler pressure based on engine speed, manifold pressure, and barometric pressure, comparing calculated and measured pressures, and implementing mitigation strategies when a predetermined threshold is exceeded, including rerouting positive crankcase ventilation gases to the intake manifold to prevent icing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a heat exchanger is used to cool compressed air in the air charger system, then combustion efficiency is improved, but water vapor condensation and freezing occur in cold climates causing intake air restriction
Solution Approach 1:
The system performs preliminary detection of icing conditions by monitoring charge air cooler pressure and comparing it to calculated expected pressure. When icing is detected, mitigation strategies are activated in advance to prevent complete air flow blockage, including rerouting PCV gases and adjusting engine operating parameters.
Solution Approach 2:
The system extracts and removes the harmful effect of water vapor by rerouting positive crankcase ventilation (PCV) gases away from the charge air cooler inlet. This prevents additional moisture from being introduced into the already problematic cooling system, thereby mitigating the icing issue while maintaining the beneficial cooling function.
2Reliability
If the charge air cooler pressure is continuously monitored and mitigation strategies are activated, then engine reliability is improved, but system complexity increases
Solution Approach 1:
The system implements feedback by continuously monitoring charge air cooler pressure with a sensor and comparing the measured pressure to the calculated expected pressure. When the difference exceeds a threshold, this feedback triggers mitigation strategies. This closed-loop feedback mechanism ensures reliable detection of icing conditions while using simple comparison logic rather than complex control algorithms.
Solution Approach 2:
The system uses existing engine parameters (engine speed, manifold pressure, barometric pressure) that are already being measured for other control functions to calculate the expected charge air cooler pressure. This self-service approach avoids the need for additional complex sensing or calculation systems, as the engine's existing sensor network provides the necessary data.
3Stress or pressure
If PCV gases are routed to the air charger system to improve crankcase ventilation, then crankcase pressure is reduced, but water vapor accumulation increases leading to icing conditions
Solution Approach 1:
The system dynamically adjusts PCV routing based on real-time conditions. When icing is detected through pressure monitoring, the system switches the PCV valve routing from the charge air cooler inlet to the intake manifold. This dynamic reconfiguration allows the system to optimize crankcase ventilation during normal operation while preventing moisture introduction during icing conditions.
Solution Approach 2:
The system changes the operating parameter of PCV routing location based on detected conditions. By switching the PCV destination between the charge air cooler inlet and the intake manifold, the system alters where crankcase gases (containing water vapor) are introduced, thereby preventing moisture accumulation in the charge air cooler while maintaining effective crankcase ventilation through alternative routing.
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 detects and mitigates air charger system icing conditions, ensuring consistent engine operation by reducing throttle body opening and adjusting gear states to maintain optimal air flow and pressure, thereby preventing engine failure due to icing.
Implementation Method 1
the heated compressed air is cooled by a heat exchanger
Implementation Method 2
the water vapor in the charged air to change phase and accumulate
Data Source
AI summary
A method to diagnose post air charger compressor icing obstructions without the addition of a post compressor pressure sensor. The method detects when conditions exists for icing to occur and performs at least one icing mitigation strategy when the icing conditions exceed a predetermined icing condition threshold.