VLC Engine Cylinder Merging for Load Control
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Solution Overview
Problem
Existing volume-controlled four-stroke reciprocating internal combustion engines require a separate expansion/compression machine, which increases installation space and production costs, and incurs additional expenses for power supply connections.
Innovation Solution
The engine operates without a separate expansion/compression machine by utilizing the first cylinder as both an expansion and compression machine, with variable timing of gas exchange valves to control fresh air quantity, and incorporates an exhaust gas heat exchanger for efficient load control, allowing the engine to operate in both two-stroke and four-stroke modes depending on load requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate expansion/compression machine is used in the intake tract, then the fresh air can be compressed or expanded to control engine load, but the installation space and production costs increase
Solution Approach 1:
The patent merges the expansion/compression function with the existing cylinder structure by operating one cylinder as an expansion machine and another as a compression machine. This integration eliminates the need for a separate expansion/compression machine, thereby reducing installation space and production costs while maintaining load control capability through the coordinated operation of these cylinders.
Solution Approach 2:
The cylinders are designed to perform multiple functions: they can operate as combustion cylinders during four-stroke cycles and as expansion/compression machines during two-stroke cycles. This multi-functionality allows the engine to achieve load control without requiring dedicated separate components, thus simplifying the overall system architecture.
2Quantity of substance
If a separate expansion/compression machine is installed, then fresh air can be compressed to increase density, but additional expenses for power supply connections are incurred
Solution Approach 1:
The expansion/compression function is performed by the engine's own cylinders using the existing crankshaft and connecting rods. The system is self-sufficient, utilizing the engine's mechanical structure to achieve air compression and expansion without requiring external power supply connections, thereby eliminating additional expenses while maintaining the ability to control fresh air density.
3Adaptability or versatility
If throttle valves are used to control air quantity, then load control is achieved, but throttle losses occur reducing efficiency
Solution Approach 1:
The patent replaces the conventional mechanical throttle valve system with a cylinder-based expansion/compression system. Instead of using throttle valves to restrict air flow and create pressure drops, the engine uses controlled expansion and compression of air in cylinders to achieve load control, thereby eliminating throttle losses and improving overall efficiency.
Solution Approach 2:
The system changes the parameter control approach from flow restriction (throttle valves) to volume change (cylinder expansion/compression). By controlling the volume of air through expansion and compression processes rather than restricting flow through throttles, the system achieves load control without the energy losses associated with throttle valves.
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 configuration reduces charge exchange losses, achieves significant efficiency improvements, and extends fuel consumption advantages to higher loads, while eliminating throttle losses and enabling a wide load range with improved response behavior.
Implementation Method 1
a heat exchanger for heating the fresh air with exhaust gas from the internal combustion engine before the fresh air is delivered to the first cylinder
Implementation Method 2
the first cylinder (VLC cylinder) is operated as an expansion machine... the fresh air is expanded in the first cylinder
Implementation Method 3
the expanded fresh air is cooled by a cooler, e.g. a charge air cooler, again to the usual fresh air temperature, before it is fed to the internal combustion engine
Data Source
AI summary
The invention relates to a volume-controlled four-stroke reciprocating internal combustion engine comprising a first cylinder, in which a first piston that is operationally connected to a crankshaft via a first connecting rod, is arranged so as to be displaceable in a reciprocating motion, and at least one second cylinder, in which a second piston that is operationally connected to the crankshaft via a second connecting rod is arranged so as to be displaceable in a reciprocating motion. The engine further includes a fresh air tract for the second cylinder, in which an expansion/compression machine is arranged in the direction of flow of fresh air before a gas exchange inlet valve of the second cylinder, wherein the expansion/compression machine is the first cylinder. The volume-controlled internal combustion engine as per the invention has great potential for saving fuel and thereby for reducing CO2.