Hydraulic Valve Control Arrangement for Zero Clearance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Internal combustion engines face challenges in achieving accurate valve timing due to clearance or lash in the force transmission chain of the valve lifting mechanism, which existing solutions have not fully addressed.
Innovation Solution
A control arrangement that adjusts the valve force transmission system to zero clearance by using a cam shaft with oblong lobes, a hydraulic fluid flow path with a non-return valve, and mechanical links to ensure precise valve operation, minimizing play and lash through hydraulic fluid pressurization and mechanical limiter mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mechanical valve lifting mechanism is used, then the structure is simple, but clearance or lash in the force transmission chain causes inaccurate valve timing
Solution Approach 1:
The patent introduces a hydraulic control arrangement with a piston unit, hydraulic control space, and non-return valve to eliminate clearance in the force transmission chain. Hydraulic fluid pressurization compensates for intentional play between cam follower unit and first piston unit, achieving accurate valve timing without complex mechanical lash adjustment mechanisms
2Manufacturing precision
If hydraulic fluid is used to minimize clearance, then valve timing accuracy improves, but the system requires additional hydraulic components and control mechanisms
Solution Approach 1:
The hydraulic system utilizes the engine's existing lubrication oil as hydraulic fluid, eliminating the need for a separate hydraulic fluid reservoir. The non-return valve automatically maintains pressure in the hydraulic control space without active control, and the system self-regulates through the cam profile geometry and hydraulic pressure dynamics
3Ease of manufacture
If intentional play is introduced in the force transmission system, then manufacturing and assembly become easier, but valve timing precision deteriorates
Solution Approach 1:
The patent changes the physical state of the force transmission system by introducing hydraulic pressure to compensate for mechanical play. The hydraulic fluid pressurization dynamically adjusts the effective clearance between components, maintaining ease of assembly while achieving precise valve timing through pressure-dependent parameter adjustment
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 solution effectively minimizes clearance in the force transmission system, ensuring accurate and efficient gas exchange valve operation by maintaining hydraulic fluid pressure and using mechanical links to compensate for intentional play, thereby enhancing engine performance.
Implementation Method 1
a hydraulic fluid flow path opening into the hydraulic control space and connectable to a hydraulic fluid supply, wherein the hydraulic fluid flow path is adapted to fill the hydraulic control space with the hydraulic fluid
Implementation Method 2
The cam device includes a cam profile having a portion arranged under a base circle of the cam profile which portion of the cam profile is arranged to control gas exchange through the inlet valve for providing a delay in the closing of the inlet valve
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Invention relates to a control arrangement (20) for a gas exchange valve (12) adapted between a cam device (18) and the gas exchange valve (12) in an internal combustion piston engine (100), comprising a mechanical limiter (42) configured to prevent movement of a first piston unit (34) in a direction closing the valve at a predetermined location of the first piston unit (34), a hydraulic control space (36) and a hydraulic fluid flow path (48) opening into the hydraulic control space (36) and connectable to a hydraulic fluid supply (50), adapted to fill the hydraulic control space (36) with the hydraulic fluid. Invention relates also to method of operating a control arrangement (20) for a gas exchange valve (12) in an internal combustion piston engine (100).