Cam-Controlled Intake Valve Actuation System
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Solution Overview
Problem
Conventional internal combustion engine systems face inefficiencies and increased complexity due to the need for variable actuation of intake valves, particularly in hybrid vehicles and simple engine designs, where energy losses occur from spring compression and hydraulic fluid management, and existing systems cannot achieve rapid opening and closing movements optimal for engine efficiency and reduced emissions.
Innovation Solution
A simplified actuation system using a mechanically controlled cam to manage the communication between a pressurized fluid volume and a lower-pressure environment, allowing for rapid intake valve opening and closing, eliminating the need for electronic control and reducing system complexity and energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a variable actuation system with electronic control valve is used to control intake valve timing, then engine efficiency and emissions are improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the electronic control valve with a purely mechanical cam-based timing control system. The cam profile is specifically designed to provide the desired valve timing characteristics without requiring electronic sensors, control units, or electronically actuated valves, thereby simplifying the system while maintaining engine efficiency
Solution Approach 2:
The patent extracts and removes the electronic control components (solenoid valves, sensors, control units) from the variable actuation system, retaining only the essential mechanical cam mechanism for timing control, thus reducing device complexity and cost
2Productivity
If rapid intake valve closing is achieved through hydraulic fluid discharge, then engine efficiency is improved, but energy losses from spring compression increase
Solution Approach 1:
The cam profile is designed to preliminary close the intake valve before the optimal timing point, allowing the valve to begin closing while still under cam control rather than allowing uncontrolled spring compression, thereby reducing energy loss while achieving rapid closing
Solution Approach 2:
The cam profile dynamically controls the valve closing process, providing a controlled rapid closure that balances the need for quick valve sealing with the need to minimize spring energy loss, rather than using a fixed mechanical or hydraulic approach
3Device complexity
If a simplified mechanical cam system is used for intake valve actuation, then device complexity is reduced, but the ability to achieve rapid opening and closing movements is limited
Solution Approach 1:
The cam profile is segmented into distinct zones: an initial rapid rise portion for quick valve opening, a plateau region for dwell time, and a controlled closure portion for rapid but energy-efficient valve closing, allowing the simple mechanical system to achieve high-speed valve actuation
Solution Approach 2:
The cam profile parameters (rise angle, dwell duration, closure angle) are specifically optimized to enable rapid valve opening and closing movements within the constraints of a simple mechanical system, achieving high-speed actuation without electronic control
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
The system achieves a rapid opening and immediate closing of intake valves, optimizing engine efficiency, reducing energy losses, and maintaining a simplified, low-cost design compatible with conventional camshaft mechanisms, while allowing for adjustable engine load through manifold pressure modulation.
Implementation Method 1
a slave piston, which actuates said intake valve and which is hydraulically controlled by said master piston, by means of a volume of pressurized fluid interposed between the master piston and the slave piston
Implementation Method 2
the intake valve is biassed by at least one spring towards a closed position
Implementation Method 3
a master piston controlled, directly or indirectly, by a first cam of a camshaft of the internal combustion engine
Data Source
Figure 1
Figure 1A~1B
Figure 1C~2
AI summary
An actuation system for actuating an intake valve associated with a cylinder of an internal combustion engine comprises a slave piston (21) that operates the intake valve (7) and that is hydraulically controlled by means of a volume of pressurized fluid (C) by a master piston (16) operated by a first cam (14A) of a camshaft (11). A control valve (24) controls the communication between the volume of pressurized fluid (C) and an environment at lower pressure to which a fluid accumulator is connected (270). The control valve (24) is mechanically controlled by a second cam (14B) that is carried by the camshaft (11) and that has the sole function of controlling the control valve (24).