Variable Valve Train Switching via Linear Actuator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable valve trains in internal combustion engines require separate hydraulic or electrical switching lines for each cylinder, which is space-consuming and costly due to tight space requirements in the cylinder head.
Innovation Solution
A variable valve train design where the valve stroke of functionally identical gas-exchange valves can be deactivated or switched independently using a single actuator module, with cam followers having primary and secondary levers and control pins connected to elongated switching elements moved by linear actuators, allowing for a space-saving and economical construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate hydraulic or electrical switching lines are provided for each cylinder, then independent switching of valve strokes for each cylinder is achieved, but the device complexity and installation space requirements increase
Solution Approach 1:
Multiple switching lines (hydraulic or electrical) for different cylinders are merged into a single common switching line. The control pins of cam followers for functionally identical valves are connected to a shared elongated switching element that can be moved by a single linear actuator, thereby reducing the number of separate switching lines while maintaining independent switching capability through the common line's ability to serve multiple functions.
Solution Approach 2:
A single switching line is designed to serve multiple cylinders and multiple cam followers simultaneously. The elongated switching element can be actuated by one linear actuator to control the switching state of multiple cam followers, making the switching line multi-functional and reducing overall system complexity.
2Ease of operation
If separate linear actuators are provided for each cylinder, then precise independent control is achieved, but the installation space and device complexity increase
Solution Approach 1:
Multiple linear actuators that would traditionally be distributed across different cylinders are merged into a single linear actuator. This single actuator controls an elongated switching element that in turn controls multiple cam followers, thereby reducing the total number of actuators and the space they occupy while maintaining precise control through the mechanical linkage system.
Solution Approach 2:
An elongated switching element acts as an intermediary between the single linear actuator and multiple cam followers. This intermediary component allows one actuator to precisely control multiple cam followers by translating the actuator's linear motion into appropriate switching actions for each cam follower through the connecting elements and control pins.
3Adaptability or versatility
If multiple elongated switching elements are arranged vertically adjacent, then independent switching for first and second gas-exchange valves is achieved, but the vertical space requirement increases
Solution Approach 1:
Instead of arranging switching elements horizontally side-by-side which would consume lateral space, the switching elements are arranged vertically adjacent to each other. This dimensional reorganization places the multiple switching elements in the vertical dimension, allowing them to share the same horizontal footprint while maintaining independent switching capability for different valve types.
Solution Approach 2:
The elongated switching elements are designed with passage openings that allow connecting elements of other switching elements to pass through. This nesting arrangement enables multiple switching elements to occupy overlapping vertical spaces without interfering with each other's operation, thereby reducing the total vertical envelope required while maintaining independent 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
Enables independent switching of valve strokes for multiple cylinders with a compact arrangement, reducing the need for additional components and installation space, while maintaining a structurally identical design for cam followers and minimizing the installation space requirements of linear actuators.
Implementation Method 1
the respective control pins of the cam follower are connected by connecting elements formed as leaf springs to an elongated switching element
Implementation Method 2
can be moved longitudinally by a linear actuator against the restoring force of a spring element from a home position into a switched position
Implementation Method 3
the linear actuators are formed as electromagnets each with an armature guided so that it can move axially in a coil body
Data Source
AI summary
A variable valve train with at least two functionally identical gas-exchange valves per cylinder, having primary cam and a secondary cam generated valve strokes that are transmitted by a switchable cam follower selectively to the gas-exchange valves. The respective cam follower has a primary lever in tapping contact with the primary cam and in switching contact with the gas-exchange valve and a secondary lever that is in tapping contact with the secondary cam and is coupleable with the primary lever by a control pin. The respective control pins are connected by connecting elements to respective first and second elongated switching elements, which are arranged above the cam followers parallel to the camshaft and are displaceable longitudinally by a linear actuator from a home into a switched position. The control pins of the cam follower of functionally identical gas-exchange valves are in switching connection with a respective one of the first and second elongated switching elements for common movement.