Variable Valve Lift Mechanism Using Latching Pin Decoupling
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Solution Overview
Problem
Existing variable valve lift mechanisms for engines are limited by constant intake valve displacement, leading to restricted engine efficiency at low-speed and low-load states, and are complicated by hydraulic pressure systems that degrade precision due to temperature sensitivity.
Innovation Solution
A variable valve lift apparatus using a latching pin mechanism to couple or decouple first and second bodies rotated by high-speed and low-speed cams, allowing for deactivation control and two-stage lift control based on engine conditions, minimizing fuel consumption and maintaining precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydraulic pressure is used to control valve lift, then the variable valve lift mechanism can control the valve in two stages, but the structure becomes complicated and workability degrades
Solution Approach 1:
The patent extracts the hydraulic pressure control system from the variable valve lift mechanism and replaces it with a purely mechanical latching pin-based decoupling mechanism. This removes the complex hydraulic components (pumps, valves, fluid channels) while retaining the two-stage control capability through mechanical means alone.
Solution Approach 2:
The patent replaces the hydraulic control system with a mechanical latching pin system. The latching pin physically couples or decouples the first body (intake cam) and second body (exhaust cam), providing two-stage control through mechanical engagement rather than hydraulic pressure, thereby simplifying the overall structure.
2Adaptability or versatility
If hydraulic pressure is used to control valve lift, then the variable valve lift mechanism can adjust the degree of lift, but the viscosity of hydraulic oil reacts sensitively to temperature causing erroneous operation and degraded precision
Solution Approach 1:
The patent replaces the temperature-sensitive hydraulic control system with a temperature-insensitive mechanical latching pin system. The mechanical coupling and decoupling of cam bodies through the latching pin provides precise valve lift control without being affected by temperature-induced changes in fluid viscosity, thereby maintaining consistent precision across varying operating conditions.
3Device complexity
If the displacement of intake valve is kept constant, then the variable valve lift mechanism structure is simplified, but the engine speed representing optimal efficiency is restricted
Solution Approach 1:
The patent introduces dynamic adjustability to the valve lift mechanism through the latching pin system that can couple or decouple the first and second bodies based on operating conditions. This allows the mechanism to adapt between different lift modes (single-stage and two-stage) dynamically, enabling the engine to achieve optimal efficiency across a broader range of speeds while maintaining structural simplicity when in constant displacement mode.
Data Source
AI summary
A variable valve lift apparatus of an engine includes a first body rotated at within a preset angle range by rotating a high-speed cam coupled to a camshaft, a second body coupled to the first body or decoupled from the first body and rotated within a preset angle range by rotating a low-cam coupled to the camshaft when the second body is decoupled from the first body, a latching pin provided retractably forward of the first body such that the first body is coupled to or decoupled from the second body, and an actuating unit to retractably actuate the latching pin. The degree of the lift of the valve is variably controlled in two stages of high-speed and low-speed modes through the rotary motion of the high speed cam or low speed cam by coupling or decoupling the first and second bodies to or from each other.