Axially Displaceable Cam Elements for Variable Valve Lift

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Solution Overview

Problem

Existing motor vehicle valve train adjustment devices lack variability and compactness, limiting their ability to efficiently manage valve lifts and cylinder deactivation functions.

Innovation Solution

A motor vehicle valve train adjustment device with axially displaceable cam elements, featuring multiple cam tracks for each cam element, allowing for variable valve lifts and integrated cylinder deactivation, along with a control and/or regulating unit for independent switching of cam elements, enabling efficient operation across different engine conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple cam elements with multiple cam tracks are used to increase variability, then the valve train adjustment device becomes more variable, but the device complexity increases

Engineering Contradiction:
ImprovevariabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The camshaft is segmented into multiple axially displaceable cam elements (at least two), each capable of independent axial movement. Each cam element can be selectively positioned to engage different cam tracks, enabling independent control of valve lifts for different cylinders. This segmentation allows the system to achieve high variability through modular configuration rather than a single complex camshaft structure.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If cam elements are designed with multiple cam tracks for different valve lifts, then the valve train adjustment device becomes more variable, but the device size increases

Engineering Contradiction:
ImprovevariabilityVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

Multiple cam tracks are arranged axially along the camshaft in the direction of axial displacement. Each cam element can be positioned at different axial locations to engage different cam tracks, effectively using the axial dimension to encode multiple valve lift options. This dimensional arrangement allows multiple functions to be packed into a compact linear space rather than requiring radial or lateral expansion.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If axially displaceable cam elements are used to enable independent control, then the valve train adjustment device becomes more variable, but the manufacturing complexity increases

Engineering Contradiction:
ImprovevariabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The cam elements are designed to be axially displaceable rather than fixed, allowing dynamic reconfiguration of the valve train during operation. Each cam element can be independently positioned along the axial direction to engage different cam tracks, enabling real-time adaptation of valve lifts based on operating conditions. This dynamic capability is achieved through simple axial movement mechanisms that maintain manufacturing feasibility.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2817494B1Internal combustion engine valve drive adjustment device
Publication Date: 2015.10.14 MERCEDES BENZ GROUP AG
  • EP2817494B1 patent drawingFigure 1~2

AI summary

The invention relates to a motor vehicle valve drive adjustment device having at least one camshaft (10) which comprises at least two cam elements (11, 12, 13, 14) arranged in an axially displaceable manner. It is proposed that a number of cam tracks (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34) for the actuation of a valve of one of the cam elements (11, 12, 13, 14) and a number of cam tracks (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34) for the actuation of a valve of another of the cam elements (11, 12, 13, 14) differ from one another.