Variable Valve Lift Apparatus Hydraulic Control
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Solution Overview
Problem
Existing variable valve lift systems fail to optimally control valve lift according to engine operation conditions, leading to inefficiencies such as power loss during valve opening and closing, and suboptimal compression ratios.
Innovation Solution
A variable valve lift apparatus featuring a latching portion with a hollow latching pin and spring mechanism, coupled with a hydraulic pressure system, allows for adjustable valve lift by selectively inserting the latching pin into a connecting hole based on hydraulic pressure, enabling Late Intake Valve Closing (LIVC) and reducing pumping loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a variable valve lift system is implemented to optimize valve lift according to engine operation conditions, then engine efficiency and compression ratio are improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical variable valve lift mechanisms with a hydraulic control system. A plunger moves axially within the tappet body under hydraulic pressure to selectively engage or disengage the latching portion, thereby controlling valve lift. This hydraulic substitution simplifies the overall mechanism while achieving variable lift functionality across different engine operating conditions.
Solution Approach 2:
The invention utilizes a hydraulic pressure chamber and plunger assembly to control the position of the latching portion. By applying hydraulic pressure to the plunger, the system achieves precise control over valve lift without requiring complex mechanical linkages or actuators, thereby improving engine efficiency while managing device complexity.
2Device complexity
If traditional valve lift control is used, then device complexity is minimized, but power loss during valve opening and closing increases
Solution Approach 1:
The patent replaces traditional mechanical valve spring-based lift control with a hydraulic actuation system. The hydraulic plunger provides controlled engagement and disengagement of the latching portion, reducing impact losses during valve opening and closing events. This substitution maintains relatively simple device architecture while significantly reducing power loss.
3Device complexity
If fixed valve lift is used, then device complexity is reduced, but engine performance under varying operating conditions deteriorates
Solution Approach 1:
The invention introduces dynamic controllability to the valve lift mechanism through a hydraulically actuated plunger. The plunger can move axially to selectively engage or disengage the latching portion, enabling the system to adapt valve lift to varying engine operating conditions. This dynamic capability improves engine performance across different regimes without requiring overly complex mechanical systems.
Solution Approach 2:
The system enables change in valve lift parameter through hydraulic pressure control of the plunger position. By varying the hydraulic pressure applied to the plunger, the valve lift can be adjusted between different positions (engaged or disengaged states), allowing optimization of engine performance for different operating conditions while maintaining manageable device complexity.
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 apparatus effectively reduces power loss and enhances engine efficiency by allowing delayed intake valve closing, thereby increasing compression ratios and improving engine performance.
Implementation Method 1
a latching pin spring which may be disposed in the hollow latching pin and engaged with the latching portion support pin to elastically support the hollow latching pin toward the plunger
Implementation Method 2
a hydraulic pressure chamber which may be formed in the outer tappet body and selectively receives hydraulic pressure, a plunger which may be slidably disposed in the outer tappet body guide hole and selectively inserts the latching portion into the latching portion connecting hole according to the hydraulic pressure supplied from the hydraulic pressure chamber
Data Source
AI summary
A variable valve lift apparatus may include an outer tappet body of which a latching portion connecting hole and an outer tappet body guide hole may be formed therewithin, an inner tappet body of which an inner tappet body guide hole may be formed therewithin and slidably disposed within the outer tappet body, a latching portion which may be disposed within the inner tappet body guide hole and selectively coupled to the latching portion connecting hole, a latching portion support pin which guides the latching portion along a longitudinal direction of the inner tappet body guide hole and may be connected to the inner tappet body, a hydraulic pressure chamber, and a plunger which may be slidably disposed in the outer tappet body guide hole and selectively inserts the latching portion into the latching portion connecting hole according to the hydraulic pressure supplied from the hydraulic pressure chamber.