Variable Valve Actuation System for Engine Mode Transition
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Solution Overview
Problem
Current engine valve actuation systems for internal-combustion engines are limited in their ability to efficiently operate across a wide range of compression ratios, especially high values, and do not effectively reduce piston pumping work or allow for smaller engine dimensions while maintaining power delivery, nor can they seamlessly transition between four-stroke and two-stroke modes without compromising efficiency.
Innovation Solution
A system that enables selective actuation of engine valves in both four-stroke and two-stroke modes by using a camshaft with a composite profile and a control unit to manage the solenoid valve, allowing for independent operation of slave pistons based on engine load conditions, combined with a phase-variator to adjust camshaft position, enabling optimal efficiency across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional single-mode valve actuation system is used, then the engine can operate reliably in one mode, but it cannot efficiently operate across a wide range of compression ratios or transition between four-stroke and two-stroke modes
Solution Approach 1:
The valve actuation system dynamically switches between four-stroke and two-stroke modes by controlling the timing and sequence of valve openings and closings. The system adapts its operation based on engine load and speed conditions, allowing the same physical hardware to perform multiple functions through dynamic control strategies rather than requiring separate mechanical systems for each mode.
Solution Approach 2:
The patent implements a universal valve actuation mechanism that can perform both four-stroke and two-stroke cycle operations using the same camshaft, valves, and actuation components. The system achieves multi-functionality through software-controlled timing sequences that dictate different valve event patterns for different operating modes, eliminating the need for mode-specific mechanical hardware.
2Power
If the engine is designed for high compression ratios, then power output is improved, but piston pumping work increases and engine dimensions must be larger
Solution Approach 1:
The system employs periodic switching between four-stroke and two-stroke operating modes based on engine load conditions. During high-load conditions, the two-stroke mode provides enhanced power delivery with reduced pumping losses, while during low-load conditions, the four-stroke mode operates for fuel efficiency. This periodic alternation allows the engine to optimize power output while minimizing cumulative pumping work across the operating cycle.
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 allows for efficient operation across a wide range of compression ratios, reduces piston pumping work, enables smaller engine designs, and facilitates seamless mode transitions between four-stroke and two-stroke operations, ensuring optimal engine performance under all conditions.
Implementation Method 1
a solenoid valve (60) configured for assuming a state in which said volume of fluid is set in communication with an outlet
Implementation Method 2
a hydraulic apparatus including: a master piston (42); a slave piston (44, 46) that can be driven by said master piston (42) by means of a volume of fluid set between said master piston (42) and said slave piston (44, 46)
Data Source
AI summary
Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.