Switchable Compressor Torque Neutral Cylinder Deactivation
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Solution Overview
Problem
Existing methods for switching internal combustion engines between full and partial load operations face challenges in maintaining torque neutrality, especially when transitioning from full engine operation to partial engine operation with cylinder deactivation, leading to reduced efficiency and usable operating range due to sluggish exhaust gas turbocharger response and increased knock tendency.
Innovation Solution
A method involving the use of a switchable compressor, such as an electrically driven compressor, to temporarily build up intake manifold pressure and adjust ignition angles, allowing for torque-neutral switching by shutting down intake and exhaust valves, thereby expanding the usable cylinder deactivation map range and improving transient operating behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If exhaust gas turbocharger is used for charging, then engine can operate in turbocharged mode, but the response is too sluggish for cylinder deactivation activation
Solution Approach 1:
The charging system is segmented into two independent parts: the exhaust gas turbocharger for baseline charging and a separate electrically driven compressor for rapid pressure build-up during transitions. This segmentation allows each component to perform its specialized function without the response limitations of a single-system approach.
Solution Approach 2:
The electrically driven compressor acts as an intermediary device that bridges the response gap between throttle actuation and cylinder deactivation. It temporarily supplies additional fresh gas to compensate for torque losses during the transition, enabling smooth activation of cylinder deactivation that would otherwise be impossible with turbocharger alone.
2Loss of energy
If cylinder deactivation is implemented, then fuel consumption is reduced, but the usable operating range is limited to naturally aspirated full load
Solution Approach 1:
The system dynamically adapts the charging strategy based on the transition phase: during cylinder deactivation activation, the electrically driven compressor provides temporary over-charging to compensate for reduced cylinder output, while in steady-state partial operation, normal turbocharger charging suffices. This dynamic approach expands the usable operating range throughout the entire map.
Solution Approach 2:
The system changes the charging parameter (fresh gas supply) by activating the electrically driven compressor only during the transient phase of cylinder deactivation. This temporary parameter change provides the additional torque needed to maintain operation in regions that would otherwise be unavailable, effectively expanding the usable operating range.
3Use of energy by moving object
If high geometric compression ratio is used, then combustion efficiency is improved, but knocking tendency increases requiring reduced volumetric efficiency
Solution Approach 1:
The electrically driven compressor operates periodically only during the brief transition phase of cylinder deactivation activation, providing temporary pressure support. This periodic action allows the system to maintain high geometric compression ratio for improved combustion efficiency while compensating for knock concerns during the specific transient period when cylinders are being deactivated.
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
Enables quick, imperceptible transitions between engine operating states, enhancing energy savings and reducing emissions by compensating for torque and filling losses during cylinder deactivation, and optimizing fuel efficiency in real driving conditions.
Implementation Method 1
the switchable compressor (18), in particular an electrically driven compressor, is started up at least temporarily to generate an additional pressure build-up in the intake manifold (26)
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention relates to a method for torque-neutrally switching a chargeable internal combustion engine (20) comprising a suction tube (26), a plurality of cylinders and a connectable, in particular electrically driven compressor (18), from a first engine operating state into a second engine operating state, and to a corresponding control unit (22). In the first engine motor state, the internal combustion engine (20) is operated in a charged state without the connectable compressor (18). In order to make the transition from the first engine operating state into the second engine operating state, inlet valves and/or outlet valves of at least one of the cylinders are shut down. In the first engine operating state, the connectable compressor (18) is at least temporarily connected in a plurality of cycles immediately prior to shutting down the inlet valves and/or outlets valves, during which the internal combustion engine (20) is throttled so as to increase pressure. The connectable compressor (18) thus at least partially generates an additional increase in pressure in the suction tube (26). The inlet valves and/or outlet valves of the at least one cylinder are shut down in the second engine operating state.