Variable Displacement Engine Cylinder Charge Air Transfer
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Solution Overview
Problem
The partial deactivation of internal combustion engines is limited by the restriction of engine speed and load range due to inadequate charge pressure at low engine speeds, primarily caused by the decrease in turbine pressure ratio and charge pressure, which is exacerbated by the configuration of exhaust-gas turbocharging and the inability to effectively increase charge pressure in auto-ignition engines.
Innovation Solution
The method involves grouping cylinders into pairs, where one cylinder remains operational and the other can be deactivated, with the deactivated cylinder acting as a charge-air supplying cylinder by transferring charge air through a flow transfer duct to the operational cylinder during the compression stroke, allowing for increased charge air supply to operational cylinders, thus expanding the usability of partial deactivation to low engine speeds and loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If exhaust-gas turbocharging is configured to increase power, then volumetric power output increases, but charge pressure decreases at low engine speeds due to lower turbine pressure ratio
Solution Approach 1:
The patent segments the charge air supply system into multiple independent pathways: the original turbocharger pathway and a new inter-cylinder charge air transfer pathway. By dividing the charge air supply function across these separate routes, the system can maintain adequate charge pressure at low engine speeds through the transfer pathway while preserving turbocharging effectiveness at higher speeds.
Solution Approach 2:
The patent introduces a flow transfer duct as an intermediary component that directly connects the charge air passage of a first cylinder to the charge air passage of a second cylinder. This intermediary structure enables charge air transfer without relying on the turbocharger, thereby resolving the charge pressure deficiency at low engine speeds while maintaining the turbocharging system for higher speed operation.
2Use of energy by moving object
If cylinder deactivation is implemented to improve efficiency at part-load, then specific fuel consumption decreases, but engine speed and load range are limited due to inadequate charge pressure
Solution Approach 1:
The patent makes the first cylinder serve multiple functions: it acts as both a combustion cylinder producing power and as a charge air supplying cylinder transferring charge air to the second cylinder during deactivation. This multi-functionality enables the system to maintain charge pressure across a broader engine speed and load range, expanding the adaptability of cylinder deactivation technology.
Solution Approach 2:
The patent changes the operational parameters of the first cylinder by controlling its inlet and outlet valves to enable charge air transfer during specific engine cycles. By adjusting valve timing and opening/closing sequences, the system transforms the first cylinder's function dynamically, allowing charge air to be transferred to the deactivated second cylinder and thereby extending the usable engine speed and load range for deactivation mode.
3Quantity of substance
If deactivated cylinders are used to supply charge air, then charge air supply to operational cylinders increases, but valve timing and control complexity increase
Solution Approach 1:
The patent implements periodic action by alternating the functional roles of cylinders based on engine operating conditions. The first cylinder periodically switches between normal combustion operation and charge air supply mode, with valve timing adjusted in discrete steps corresponding to different engine loads and speeds. This periodic switching manages control complexity by using standardized valve timing patterns rather than continuous adjustment.
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 enhances the torque characteristic and expands the load range for partial deactivation, improving engine efficiency and fuel consumption by ensuring adequate charge air supply to operational cylinders independent of compressor power, thereby optimizing partial deactivation in supercharged auto-ignition engines.
Implementation Method 1
at least one exhaust-gas turbocharger (90) is provided which comprises a turbine (92) arranged in the exhaust-gas discharge system and a compressor (94) arranged in the intake system
Implementation Method 2
at least one exhaust-gas turbocharger (90) is provided which comprises a turbine (92) arranged in the exhaust-gas discharge system and a compressor (94) arranged in the intake system
Data Source
AI summary
Methods and systems are provided for a variable displacement engine. In one example, a method may include flowing charge air from a deactivated cylinder to an adjacent firing cylinder.