Switchable Valve Bridge with Locking Collar
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Solution Overview
Problem
Current valve drives for internal combustion engines lack a efficient mechanism for switchable valve deactivation and variable valve lift, which are crucial for improving engine performance, efficiency, and emissions.
Innovation Solution
A switchable valve bridge system with a locking collar, ramps, and a mechanical lash adjustment ring that allows for axial and radial movement to engage and disengage locking latches, enabling the system to transition between locked and unlocked positions using an electrical actuator, facilitating valve deactivation or variable lift without hydraulic pressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hydraulic pressurization system is used for valve actuation, then precise valve lift control is achieved, but system complexity and cost increase
Solution Approach 1:
The patent replaces the hydraulic actuation system with a purely mechanical linkage system. The rocker arm directly transmits motion from the camshaft to the valve stem through a mechanical connection, eliminating the need for hydraulic pumps, pressure control valves, and fluid delivery systems while maintaining precise valve lift control through cam profile design.
Solution Approach 2:
The invention extracts and removes the hydraulic system components from the valve actuation mechanism. By taking out the hydraulic pressurization subsystem, the patent simplifies the overall system architecture while retaining the essential valve lift control function through direct mechanical means.
2Productivity
If valve deactivation mechanism is implemented, then engine efficiency improves, but device complexity increases
Solution Approach 1:
The patent implements a dynamic valve bridge system where the rocker arm can be selectively positioned in different states: engaged with the valve stem for active operation, or disengaged for valve deactivation. This dynamic reconfigurability allows the system to adapt its functionality based on operating conditions, improving engine efficiency without requiring completely separate mechanisms for each mode.
3Manufacturing precision
If mechanical lash adjustment is used, then manufacturing precision is improved, but ease of operation decreases
Solution Approach 1:
The patent employs a self-adjusting mechanical lash compensation mechanism where the rocker arm design inherently accommodates valve stem clearance variations. The mechanical linkage automatically compensates for lash changes through its geometric design and tolerances, eliminating the need for manual adjustment operations while maintaining precise valve clearance control.
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 system effectively adjusts mechanical lash and enables efficient valve operation, allowing for both full and partial valve lift, enhancing engine performance and emissions control through electro-mechanical actuation.
Implementation Method 1
the return spring can engage either the ramp or the locking collar
Implementation Method 2
the lost motion spring is arranged within a bore of the outer housing such that the inner housing and the lost motion spring are arranged in series within the bore
Implementation Method 3
The first ramp is configured to be actuated by the locking collar such that axial movement of the first ramp causes radial movement of the first locking latch
Data Source
AI summary
A switchable valve bridge for an internal combustion engine is provided that includes an outer housing, an inner housing, a locking collar, and a first ramp. The outer housing includes two valve pallets configured to interface with two poppet valves. The inner housing is slidably disposed within the outer housing. The inner housing has a first locking latch configured to move radially relative to an actuation axis of the inner housing. The locking collar is configured to move axially via an actuation force applied to the locking collar in a first axial direction parallel to the actuation axis. The first ramp is disposed within both the first locking aperture and the locking collar. The first ramp is configured to be actuated by the locking collar such that axial movement of the first ramp causes radial movement of the first locking latch.