Variable Geometry Turbocharger Control for Miller Cycle Oil Consumption
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Solution Overview
Problem
Early intake valve closing in internal combustion engines during Miller cycling can lead to reduced in-cylinder pressure below crankcase pressure, potentially causing oil consumption due to operational challenges, which existing technologies have not adequately addressed.
Innovation Solution
A multi-cylinder internal combustion engine system equipped with a variable geometry turbocharger (VGT) that increases intake manifold pressure when in-cylinder pressure drops below crankcase pressure, using a controller to monitor and predict pressure conditions and adjust VGT operation accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If early intake valve closing is employed for Miller cycle operation, then efficiency improves and NOx reduces, but in-cylinder pressure drops below crankcase pressure causing oil consumption
Solution Approach 1:
The system applies preliminary anti-action by using the VGT to increase intake manifold pressure before the early intake valve closing event occurs. This pre-pressurization of the intake manifold prevents the in-cylinder pressure from dropping below crankcase pressure during the expansion stroke, thereby counteracting the oil consumption problem before it occurs while maintaining the efficiency benefits of early valve closing
Solution Approach 2:
The invention changes the pressure parameter in the intake manifold by dynamically adjusting the VGT vane position. This parameter change increases the intake manifold pressure to compensate for the pressure drop that would otherwise occur with early intake valve closing, allowing the engine to maintain Miller cycle efficiency without suffering from oil consumption issues
2Loss of energy
If early intake valve closing is used before bottom dead center, then Miller cycling efficiency improves, but operational reliability deteriorates due to oil being pulled past piston rings
Solution Approach 1:
The system employs feedback control by using sensors to monitor intake manifold pressure and VGT vane position, and using this information to dynamically adjust the VGT operation. The controller continuously adjusts the intake manifold pressure based on actual operating conditions to prevent in-cylinder pressure from dropping below crankcase pressure, thereby maintaining both efficiency and operational reliability
Solution Approach 2:
The VGT system applies preliminary anti-action by proactively increasing intake manifold pressure in anticipation of the early intake valve closing event. This prevents the harmful condition of negative pressure differential that would cause oil consumption, thereby maintaining operational reliability while enabling efficient Miller cycle 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 solution effectively reduces or prevents oil consumption during early intake valve closing by maintaining adequate intake manifold pressure, enabling the use of early intake valve closing in Miller cycle operations while minimizing operational challenges.
Implementation Method 1
A VGT that is used to increase intake manifold pressure during conditions in which the in-cylinder pressure can drop below crankcase pressure
Data Source
AI summary
Systems, apparatus, and methods are disclosed that include an internal combustion engine having a plurality of cylinders and controlling a variable geometry turbocharger during early intake valve opening to reduce or prevent oil consumption.