Lost Motion Differential Valve Actuation System
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Solution Overview
Problem
Current variable valve actuation (VVA) systems in internal combustion engines require multiple hydraulic switching components and electronics for each valve, leading to increased cost and complexity, making it difficult to optimize valve opening/closing times and lift for varying engine conditions.
Innovation Solution
A system comprising master and slave pistons, an accumulator, and a mode selector valve allows for differential actuation of engine valves, enabling separate control of valve lift and duration without the need for dedicated components for each valve, using hydraulic communication and a two-way valve to selectively connect or isolate the pistons and accumulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If each valve is equipped with its own hydraulic switching components and electronics for variable valve actuation, then valve timing and lift can be optimized for different engine operating conditions, but system complexity and cost increase significantly
Solution Approach 1:
The patent combines multiple valve actuation functions into a single integrated system. A first master piston controls both a first slave piston (connected to first valve) and a second slave piston (connected to second valve). This merging of control functions reduces the number of independent hydraulic switching components needed, thereby reducing system complexity while maintaining the ability to independently actuate multiple valves.
Solution Approach 2:
The first master piston serves multiple functions: it can independently control the first slave piston, independently control the second slave piston, or control both simultaneously. This multi-functional design allows a single component to replace what would traditionally require multiple separate components, reducing overall system complexity while preserving adaptability for different valve actuation scenarios.
2Device complexity
If fixed profile cams are used for valve actuation, then the system is simple and reliable, but it is difficult to adjust valve timing and lift for optimizing performance under various engine conditions
Solution Approach 1:
The patent replaces static fixed profile cams with a dynamic hydraulic actuation system. The master and slave pistons, along with controllable valve members, enable real-time adjustment of valve timing and lift based on engine operating conditions. This dynamic system allows the valve train to adapt its characteristics rather than being constrained by a fixed cam profile.
Solution Approach 2:
The patent employs hydraulic principles to achieve variable valve actuation. Master and slave pistons connected through hydraulic fluid transmission enable precise control of valve timing and lift. The hydraulic system allows for smooth, continuous adjustment of valve actuation parameters, providing adaptability that mechanical cam profiles cannot achieve.
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 solution reduces the complexity and cost of VVA systems by enabling flexible valve actuation without dedicated components for each valve, improving engine efficiency and allowing for optimized valve operation across varying engine conditions.
Implementation Method 1
a first slave piston operatively connected to the first engine valve and configured to hydraulically receive the first valve actuation motions from at least the first master piston
Implementation Method 2
an accumulator and a mode selector valve in hydraulic communication with the first master piston, the first slave piston and the accumulator
Data Source
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AI summary
In an engine comprising a cylinder having first and second engine valves of a same function type, a system for actuating the first and second engine valves comprises a first and second master pistons that receive first and second valve actuation motions from respective ones of a first and second valve actuation motion source, a first slave piston operatively connected to the first engine valve and configured to hydraulically receive the first valve actuation motions from at least the first master piston and a second slave piston operatively connected to the second engine valve and configured to hydraulically receive the second valve actuation motions from the second master piston. The system further comprises an accumulator and a mode selector valve in hydraulic communication with the first master piston, the first slave piston and the accumulator. The mode selector valve may selectively hydraulically connect the first master piston to the accumulator.