Fluid Virtual Piston for Variable Compression Ratio Control
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Solution Overview
Problem
Existing internal combustion engines face challenges in achieving energy efficiency and reducing polluting emissions, particularly at low RPM and load conditions, and struggle with controlling detonation and meeting environmental standards due to mechanical complexities and weight increases.
Innovation Solution
A system is introduced that uses a fluid as a secondary piston for compression, managed by a micro-valve controlled by the engine control unit, to create a variable compression ratio without altering the engine's structure or operation, allowing for controlled auto-ignition and improved mixing of air/fuel mixtures, reducing pollutants like NOx and CO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable compression ratio systems with mechanical moving parts are used, then energy efficiency and emission control improve, but weight, friction, device complexity, and center of gravity position worsen
Solution Approach 1:
The patent replaces mechanical variable compression ratio systems with a fluid-based system. A second piston filled with compressible fluid (gas or liquid) is introduced into the combustion chamber, actuated by a compact actuator rather than complex mechanical linkages. This substitution eliminates numerous mechanical moving parts while achieving variable compression ratio control through fluid pressure manipulation.
Solution Approach 2:
The invention employs pneumatic or hydraulic principles by using a compressible fluid contained in a second piston to achieve compression ratio variation. The fluid pressure is controlled by an actuator to move the second piston, thereby varying the compression volume. This approach uses fluid mechanics instead of mechanical linkages to achieve the desired variable compression effect.
2Loss of energy
If direct injection and exhaust gas recirculation are used, then energy efficiency and emission control improve, but reliability at low RPM and load deteriorates
Solution Approach 1:
The patent changes the compression ratio parameter dynamically to optimize engine operation across different operating conditions. By varying the compression ratio through the second piston mechanism, the engine can maintain stable combustion and reliable operation at low RPM and load conditions while preserving the energy efficiency benefits of direct injection and exhaust gas recirculation.
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 system enhances energy efficiency, reduces pollutant emissions, and allows for operation closer to stoichiometric conditions, increasing torque and reducing temperature peaks, while maintaining pressure levels, without increasing weight or mechanical complexity.
Implementation Method 1
the air/fuel mixture (or air only for diesel engines) is essentially confined in the clearance volume (4 and 5). At this time, the second compression occurs by the introduction of a fluid by the micro-valve (3)
Implementation Method 2
The scale of the vortex structures is conditioned by the cross-section surface of the duct
Implementation Method 3
the burnt gases of the preceding cycle stuck in the duct of the clearance volume (5) insulate the air/fuel mixture from the fluid
Implementation Method 4
The present invention also allows to control the moment of auto-ignition for the HCCI engine
Data Source
AI summary
The invention relates a system for an internal combustion engine using a fluid as a virtual fast piston with variable stroke. This system enables the engine to behave like a variable compression ratio engine. It consists of a duct relatively long and narrow serving as a cylinder for the virtual piston and opening into a valve. This duct is an extension of the clearance volume in the cylinder head of the engine. When the piston arrive near to the top dead center, a second compression of the air/fuel mixture is carried out by introducing a fluid at high-pressure via a valve. The introduction of fluid in a duct is manifested as a jet of fluid without mixing with the air/fuel mixture. This system allows regardless of the load, to regulate the pressure at the ignition of combustion and to increase the quantity of matter in the cylinder, despite the air/fuel mixture is close to Stochiometric proportions.