Compressor Recirculation Valve Control for Charge Air Cooler Condensate
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Solution Overview
Problem
Existing engine systems face issues with condensate formation in charge air coolers due to increased induction pressure, which can lead to engine misfire and combustion instability, particularly during conditions of high humidity or when the induction pressure exceeds atmospheric pressure.
Innovation Solution
The method involves adjusting the compressor recirculation valve and wastegate to decrease induction pressure by opening them when condensate forming conditions are detected, such as high humidity or induction pressure exceeding atmospheric pressure, and closing them when the pressure returns to normal or torque demand increases, thereby reducing condensate formation in the charge air cooler.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the compressor recirculation valve is closed to maintain boost pressure, then the induction pressure increases to meet torque demand, but condensate forms in the charge air cooler when induction pressure exceeds atmospheric pressure during high humidity conditions
Solution Approach 1:
The compressor recirculation valve is dynamically controlled based on real-time monitoring of induction pressure and humidity conditions. The valve transitions between closed and open states according to whether condensate formation conditions exist, allowing the system to adapt its boost pressure control strategy to prevent condensate while meeting torque demands when conditions permit
Solution Approach 2:
The system changes the induction pressure parameter by opening the compressor recirculation valve when condensate formation conditions are detected. This parameter change reduces the induction pressure below atmospheric pressure, preventing condensate formation in the charge air cooler while allowing the system to return to normal boost operation when conditions improve
2Object-affected harmful factors
If the compressor recirculation valve is opened to reduce induction pressure and prevent condensate formation, then condensate formation is reduced, but the induction pressure becomes less than required to produce the manifold pressure needed for torque demand
Solution Approach 1:
The valve control strategy dynamically switches between two operational modes: when condensate formation conditions exist, the valve opens to reduce induction pressure; when these conditions do not exist, the valve closes to maintain boost pressure. This dynamic switching ensures torque demand is met whenever possible while preventing condensate formation when environmental conditions require it
Solution Approach 2:
The system takes preliminary action by opening the compressor recirculation valve before condensate can form in the charge air cooler. By detecting high humidity and induction pressure conditions in advance, the system prevents condensate formation rather than reacting to it after it occurs
3Stability of the object's composition
If the compressor recirculation valve remains closed under conditions when increased boost is not required, then the valve builds up induction pressure before the throttle, but this increases the potential for condensate formation in the charge air cooler
Solution Approach 1:
The control system uses feedback from humidity sensors and pressure sensors to continuously monitor conditions in the intake system. When feedback indicates high humidity and induction pressure above atmospheric, the system responds by opening the compressor recirculation valve to reduce pressure, preventing condensate formation while maintaining stable system operation
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 effectively reduces condensate formation in the charge air cooler, minimizing the risk of engine misfire and combustion instability by maintaining optimal induction pressure and preventing condensate ingestion during increased airflow conditions.
Implementation Method 1
an intercooler or charge air cooler (CAC) may be utilized to cool the heated air thereby increasing its density
Implementation Method 2
Condensate may form in the CAC when the ambient air temperature decreases, or during humid or rainy weather conditions, where the intake air is cooled below the water dew point temperature
Implementation Method 3
a compressor recirculation valve (CRV) to divert intake air around a compressor of the turbocharger to control an amount of boost provided to an intake manifold of the engine
Implementation Method 4
a turbocharger or supercharger to compress ambient air entering the engine in order to increase power. Compression of the air may cause an increase in air temperature
Data Source
AI summary
Methods and systems are provided for adjusting a compressor recirculation valve in response to condensate forming conditions in a charge air cooler (CAC). In one example, a compressor recirculation valve may be opened in response to an induction pressure greater than a threshold pressure when the induction pressure is greater than required to produce a manifold pressure required for a torque demand. Further, a wastegate may be opened to further reduce the induction pressure during certain driving conditions.