Lost Motion Valve Actuation with Wedge Locking Elements
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Solution Overview
Problem
Existing engine valve actuation systems face challenges in adjusting valve timing and lift for optimal performance across varying engine conditions, often resulting in increased cost, size, and reduced reliability due to the need for additional components and complex packaging.
Innovation Solution
A system utilizing a lost motion assembly with locking elements, such as wedges, to selectively lock and unlock valve actuation mechanisms within the valve train, allowing for variable valve timing and lift adjustments through hydraulic actuation, combining with cam phase shifting and variable valve actuation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable valve timing and lift systems are added to adjust valve timing for optimal performance, then engine performance and efficiency are improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the variable valve timing control function with the existing cam phase shifting mechanism by integrating a lost motion assembly into the valve train. This merging approach allows the system to achieve variable valve timing capability without adding a completely separate control system, thereby improving engine performance while limiting the increase in device complexity.
Solution Approach 2:
The lost motion assembly is designed to serve multiple functions: it controls valve timing, provides valve lift adjustment, and integrates with the existing cam phase shifting mechanism. This multi-functionality allows a single component to address multiple performance requirements, improving engine efficiency without proportionally increasing system complexity.
2Adaptability or versatility
If additional components are added for valve timing adjustment, then valve timing control capability is improved, but space requirements and packaging difficulty increase
Solution Approach 1:
The lost motion assembly is nested within the existing valve train structure, utilizing available spaces within the rocker arm or valve bridge housing. This nesting approach allows the additional control components to be accommodated within the existing packaging envelope, improving valve timing control capability without significantly increasing space requirements.
Solution Approach 2:
The patent utilizes the vertical dimension within the valve train by employing a plunger-based lost motion mechanism that moves axially within the rocker arm or valve bridge. This dimensional approach allows control components to be arranged vertically rather than horizontally, optimizing space utilization and fitting within existing packaging constraints.
3Manufacturing precision
If complex valve actuation systems are implemented, then valve timing precision is improved, but reliability decreases
Solution Approach 1:
The lost motion assembly utilizes spring-loaded plungers and mechanical locking elements that automatically engage and disengage based on hydraulic pressure changes. This self-service mechanism eliminates the need for complex electronic sensors and actuators, achieving precise valve timing control while maintaining high reliability through passive mechanical operation.
Solution Approach 2:
The patent replaces complex electronic control systems with a mechanically-based lost motion assembly that uses hydraulic pressure to control plunger movement. This substitution of mechanical/hydraulic elements for electronic components simplifies the control system, improving reliability while maintaining precise valve timing through direct mechanical linkage.
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 engine performance and efficiency during engine braking operations while maintaining low cost, high reliability, and minimizing space requirements by enabling flexible valve actuation strategies.
Implementation Method 1
The locking elements comprise wedges having at least one wedge inclined surface defined according to a cone frustum and configured to engage an outer recess formed in a housing
Implementation Method 2
allowing for variable valve timing and lift adjustments through hydraulic actuation
Data Source
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AI summary
A system for actuating one or more engine valves comprises a lost motion assembly including locking elements to selectively lock and unlock a locking mechanism disposed within a valve train such that motions may be likewise selectively applied to, or prevented from being applied to, one or more engine valves. In an embodiment, the locking elements comprise wedges having at least one wedge inclined surface defined according to a cone frustum and configured to engage an outer recess formed in a housing, the outer recess comprising an outer recess inclined surface also defined according to the cone frustum. The device may comprise a locking mechanism disposed within a housing bore in the housing and a snubber also disposed in the housing bore. Furthermore, the outer recess may be configured to permit movement of the locking element along a longitudinal axis of the housing bore.