Variable Valve Lift Roller Rocker Mechanism
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Solution Overview
Problem
Existing internal combustion engines face inefficiencies due to fixed valve lift structures that fail to adapt to varying operating conditions, leading to suboptimal combustion and fuel economy at different speeds.
Innovation Solution
A variable valve lift device using a roller rocker arm lift mechanism and a driving mechanism, where a motor-controlled second rocker arm with a slide track allows adjustable valve lift, enabling continuous variable lift from low to high speeds, optimizing valve lift across the engine's speed range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed and constant valve lift structure is employed, then the structure is simple and reliable, but the valve lift cannot be adapted to different working conditions and speeds, resulting in suboptimal combustion and fuel economy
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed valve lift structure into a dynamically adjustable one. The rocker arm is designed with a movable fulcrum that can change its position along the rocker arm body, enabling continuous adjustment of valve lift. This allows the system to adapt to different working conditions and speeds while maintaining a relatively simple mechanical structure without complex control systems.
Solution Approach 2:
The patent implements parameter changes by allowing the fulcrum position parameter to vary. By changing the fulcrum position along the rocker arm, the valve lift parameter is continuously adjusted. This simple parameter change mechanism enables the system to optimize combustion and fuel economy across different operating conditions without requiring complex multi-parameter control systems.
2Quantity of substance
If a large valve lift is used at low speed, then more inlet gas can be brought in, but the flow inertia is small causing hindered gas swirl creation and unhomogeneous fuel-air mixture
Solution Approach 1:
The dynamic fulcrum position adjustment allows the valve lift to be optimized for different speed conditions. At low speeds, the fulcrum position is adjusted to provide smaller valve lift, which maintains appropriate gas swirl and homogeneous fuel-air mixture. At high speeds, the fulcrum position changes to provide larger valve lift, increasing inlet gas quantity. This dynamic adaptation eliminates the harmful effects of inappropriate valve lift at different speeds.
3Device complexity
If a small valve lift is used at high speed, then the structure is simpler, but the flow inertia is large creating strong gas swirl that is adverse to combustion
Solution Approach 1:
The dynamic fulcrum adjustment mechanism enables the valve lift to increase with engine speed. At high speeds, the fulcrum position is automatically adjusted to provide larger valve lift, which reduces gas swirl intensity and improves combustion. This maintains combustion quality across the entire speed range without requiring complex external control systems.
4Quantity of substance
If oversize valve lift is used at low speed under throttle influence, then inlet gas quantity increases, but pump gas loss occurs and internal energy is consumed reducing working efficiency
Solution Approach 1:
The dynamic fulcrum position adjustment prevents pump gas loss by providing appropriate valve lift for each operating condition. At low speeds under throttle influence, the fulcrum position is adjusted to provide optimal valve lift that maintains gas swirl and homogeneous mixture without excessive lift that would cause pump gas loss. This improves working efficiency across all operating conditions.
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 provides improved fuel economy and power performance by allowing flexible adjustment of valve lift according to engine conditions, ensuring optimal operation across the full speed range with a simple and fast response system.
Implementation Method 1
a cam and a roller of the roller rocker arm lift mechanism cooperates with each other so as to control the valve lift
Implementation Method 2
the rocker-arm pin can slide in the slide track of the second rocker arm
Implementation Method 3
the driving mechanism comprises a linear motor and an output shaft; the linear motor drives the output shaft
Implementation Method 4
the driving mechanism comprises a control motor, an output shaft, a gear and a rack; the gear engages with the rack
Implementation Method 5
the driving mechanism comprises a control motor, a worm, a worm wheel, an output shaft, a gear and a rack; the control motor drives the worm and the worm wheel
Data Source
AI summary
A variable valve lift system for an internal combustion engine includes a roller rocker lift mechanism and a driving mechanism. A cam and a roller of the roller rocker lift mechanism cooperate with each other to control valve lift. The roller rocker lift mechanism includes a second rocker arm, wherein one end of the second rocker arm is connected with the driving mechanism by a rotation pin so as to create a straight-line displacement of the driving mechanism; the second rocker arm is provided with a guideway in the direction of the straight-line displacement; a rocker-arm pin of the roller rocker lift mechanism is slidably set in the guideway of the second rocker. According to actual work condition of the internal combustion engine, the valve lift is regulated by a motor; and continuous variable valve lift is provided from low speed to high speed.